>>> from percentatge import increment

>>> round(increment(100, 120), 1)
20.0
>>> round(increment(1000, 1120), 1)
12.0
>>> round(increment(1000, 1100), 1)
10.0
>>> round(increment(1000, 1150), 1)
15.0
>>> round(increment(1000, 1650), 1)
65.0
>>> round(increment(200, 260), 1)
30.0
>>> round(increment(200, 240), 1)
20.0
>>> round(increment(200, 210), 1)
5.0
>>> round(increment(200, 215), 1)
7.5
>>> round(increment(200, 213), 1)
6.5