Level 9: 70 people, 70 jobs

One of the things you need to look out for: If your people aren't happy, your buildings won't be fully occupied. If you were counting on hitting a bonus level, such as "50 people," to get the resources you need to take the next step, this can be a real problem.

Note the 2 out of potentially 10 people at 75% happiness just after I got level 7. It's important to set a pace and order of construction that keeps your happiness up so you have full occupancy and full employment. Lack of employment doesn't seem to harm happiness. Build homes first then commercial buildings.

If there aren't enough people to fill the jobs, you won't make the full income potential. In fact, if you don't have enough people, it's possible to make no money if there are no people available to employ.