Its actually pretty simple.
Pop Modifier 1 Population Amount := 19
This is the population amount it takes to get this bonus. SEV uses the highest amount. So if you have 3 modifiers at 10, 20, and 30, and your population is 25, it'll use the 20 modifier.
Pop Modifier 1 Production Modifier Percent := 100
This is the amount production (all resources including research and intelligence) changes. Just multiply this by the amount produced.
Pop Modifier 1 SY Rate Modifier Percent := 100
Same thing as production, except for construction.
The big jump at the end is because MM didn't bother to add any in between.
I have no idea what the max values are, but I doubt its 200.