Class M planets are characterized by fertile lands, temperate climates and big oceans. They are also the most common planet type. This makes them the main source of food and water in the universe. They depend on a steady supply of energy.
Worker increase per cycle (3 hours) is a random value between 1.2% and 2.4% plus above-mentioned bonuses when upkeep is met.
If upkeep is not met workers leave.
When population is over 100,000, an overcrowding-effect takes place and growth will slow down with increasing population. For very big planets and starbases there may happen a worker-decrease, even if all upkeep is provided.