The judge in the provided example picked values within the ranges provided on each row - he or she wasn't using a system - which is a completely valid way to do it. He or she decided to go 50% all the way down.
So the short answer is that the percentages don't matter as long as you're picking something within the ranges on the new row.
The values given on each row are just guidelines to show you what would be generally expected.
A longer answer and/or example:
So, Achea has 40,000 families, and an original assumption that 10% of that, 4,000, is the urban population. That puts it at Row 7 on the Villages/Towns/Cities placement table, bolded and italicized:
Realm/Domain
<p><strong>Population</strong></p>
<p><strong>(families)</strong></p>
</td>
<td>
<p><strong>Urban</strong></p>
<p><strong>Population</strong></p>
<p><strong>(families)</strong></p>
</td>
<td>
<p><strong>Largest</strong></p>
<p><strong>Settlement</strong></p>
<p><strong>(families)</strong></p>
</td>
<td>
<p> </p>
<p><strong>Monthly</strong></p>
<p><strong>Income</strong></p>
</td>
<td>
<p> </p>
<p><strong>Market</strong></p>
<p><strong>Class</strong></p>
</td>
</tr>
</tbody>
<tbody>
<tr>
<td>
<p><em><strong>31,250-62,499</strong></em></p>
</td>
<td>
<p><em><strong>3,125-6,249</strong></em></p>
</td>
<td>
<p><em><strong>Large town (625-1,249)</strong></em></p>
</td>
<td>
<p><em><strong>370-739gp</strong></em></p>
</td>
<td>
<p><em><strong>Class IV</strong></em></p>
</td>
</tr>
<tr>
<td>
<p><span style="color:#A9A9A9">62,500-124,999</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">6,250-12,499</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">Small city (1,250-2,499)</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">740-1,474gp</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">Class IV</span></p>
</td>
</tr>
<tr>
<td>
<p><span style="color:#A9A9A9">125,000-249,999</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">12,500-24,999</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">City (2,500-4,999)</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">1,475-2,950gp</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">Class III</span></p>
</td>
</tr>
</tbody>
|
Note each row gives you ranges of 10% of the total population for Urban Population, then 20% of that for the Largest Settlement.
We want more folks in the urban areas, so we shift down two rows, from Row 7, in the Urban Population Column.
Realm/Domain
<p><strong>Population</strong></p>
<p><strong>(families)</strong></p>
</td>
<td>
<p><strong>Urban</strong></p>
<p><strong>Population</strong></p>
<p><strong>(families)</strong></p>
</td>
<td>
<p><strong>Largest</strong></p>
<p><strong>Settlement</strong></p>
<p><strong>(families)</strong></p>
</td>
<td>
<p> </p>
<p><strong>Monthly</strong></p>
<p><strong>Income</strong></p>
</td>
<td>
<p> </p>
<p><strong>Market</strong></p>
<p><strong>Class</strong></p>
</td>
</tr>
</tbody>
<tbody>
<tr>
<td>
<p><em><strong>31,250-62,499</strong></em></p>
</td>
<td>
<p><span style="color:#A9A9A9">3,125-6,249</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">Large town (625-1,249)</span></p>
</td>
<td>
<p><span style="color:#A9A9A9"><em><strong>3</strong></em>70-739gp</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">Class IV</span></p>
</td>
</tr>
<tr>
<td>
<p><span style="color:#A9A9A9">62,500-124,999</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">6,250-12,499</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">Small city (1,250-2,499)</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">740-1,474gp</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">Class IV</span></p>
</td>
</tr>
<tr>
<td>
<p><span style="color:#A9A9A9">125,000-249,999</span></p>
</td>
<td>
<p><em><strong>12,500-24,999</strong></em></p>
</td>
<td>
<p><em><strong>City (2,500-4,999)</strong></em></p>
</td>
<td>
<p><em><strong>1,475-2,950gp</strong></em></p>
</td>
<td>
<p><em><strong>Class III</strong></em></p>
</td>
</tr>
</tbody>
|
Implied there is a shift downward on the Largest Settlement size as well - it's more people living in the same number of urban settlements, not more urban settlements over all (though you could do that)
At this step, there's a few ways to figure out your new Urban Population
You could do it by making it up, that's what happened here. The Judge pegged his new Urban Population at 20K families, which is 50% of his total population of 40K. Picking pretty much anything within that range of 12.5K->24.9K would be fine.
You could also do it by ratio - which is what I do because I'm OCD about dumb stuff - we originally said 40K/4K rural and urban. 4,000 urban families is 28% through the 3125-6249 range of Urban Population in Row 7. So, by ratio, 28% through the 12.5K-25K range in Row 9 would be about 16K urban families.
The second step down takes our Largest Settlement to Row 11.
Realm/Domain
<p><strong>Population</strong></p>
<p><strong>(families)</strong></p>
</td>
<td>
<p><strong>Urban</strong></p>
<p><strong>Population</strong></p>
<p><strong>(families)</strong></p>
</td>
<td>
<p><strong>Largest</strong></p>
<p><strong>Settlement</strong></p>
<p><strong>(families)</strong></p>
</td>
<td>
<p> </p>
<p><strong>Monthly</strong></p>
<p><strong>Income</strong></p>
</td>
<td>
<p> </p>
<p><strong>Market</strong></p>
<p><strong>Class</strong></p>
</td>
</tr>
</tbody>
<tbody>
<tr>
<td>
<p><em><strong>31,250-62,499</strong></em></p>
</td>
<td>
<p><span style="color:#A9A9A9">3,125-6,249</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">Large town (625-1,249)</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">370-739gp</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">Class IV</span></p>
</td>
</tr>
<tr>
<td>
<p><span style="color:#A9A9A9">62,500-124,999</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">6,250-12,499</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">Small city (1,250-2,499)</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">740-1,474gp</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">Class IV</span></p>
</td>
</tr>
<tr>
<td>
<p><span style="color:#A9A9A9">125,000-249,999</span></p>
</td>
<td>
<p><em><strong>12,500-24,999</strong></em></p>
</td>
<td>
<p><span style="color:#A9A9A9">City (2,500-4,999)</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">1,475-2,950gp</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">Class III</span></p>
</td>
</tr>
<tr>
<td>
<p><span style="color:#A9A9A9">250,000-499,999</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">25,000-49,999</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">Large city (5,000-9,999)</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">4,700-9,399gp</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">Class II</span></p>
</td>
</tr>
<tr>
<td>
<p><span style="color:#A9A9A9">500,000-749,999</span></p>
</td>
<td>
<p><span style="color:#A9A9A9">50,000-74,999</span></p>
</td>
<td>
<p><em><strong>Large city (10,000-14,999)</strong></em></p>
</td>
<td>
<p><em><strong>9,400-14,099gp</strong></em></p>
</td>
<td>
<p><em><strong>Class II</strong></em></p>
</td>
</tr>
</tbody>
|
Again, in the book, the presiding Judge decided to wing it and pick 10K families, going with 50% again.
By our previously calculated 28%, I would set my largest settlement size at 11.4K families. (28% of the range of 5000 on Row 11)
In a default 40K realm, the urban population is 10% of the total (4K) , and 20% (800 families) of the urban population lives in the largest settlement.
The Judge in the book took a 40K family domain, and gave it a total urban population of 20K families (50%) with a Large City of 10K families (50% of that).
My method took that 40K domain, gave it a total urban population of 16K (40%) and a Large City of 11.4K families (71% of that).
They're both within the general ranges, though I like mine better because it's much more City-State-y.