Random encounter question

When a Dragon random encounter is rolled, how does one determine how many, and how old, the dragons are?

Not an Autarch, but:

At least in my campaign, based on the relative HD and abilities of dragons, I would roll:

Wilderness: 2d6, take the lower die.
Dungeon: Use the dungeon level as the roll result.

1: Spawn
2: Very Young
3: Young
4: Juvenile
5: Adult
6: Mature Adult

In both cases, if you want a HD 14+ dragon, you would place it manually, much like you would a 14th level Emperor.

I think Alex posted a table some time ago that included the older dragons as well:

I would recommend using 2d4:

2 - Spawn
3 - V. Young
4 - Young
5 - Juvenile
6 - Adult
7 - Mature Adult
8 - Old

If you roll an 8, roll 1d6-3. On a 1, the dragon is Very Old, on a 2 Ancient, and on a 3 Venerable.