Zorg Empire

In the information section of solar plants, it provides a whole heap of numbers.

eg,
19 4.648 (645) -733
20 5.381 (1.378) 0
21 6.216 (2.213) 835
^
what do the green numbers in brackets represent?

How much of an increase it provides over the last level.

wow i'm dense, i didn't even consider trying to see if there was a correlation there lol.