step,ser
7500,0.1025390625
7750,0.09036458333333333
8000,0.08580729166666666
8250,0.07532552083333334
8500,0.07350260416666667
8750,0.07864583333333333
9000,0.06575520833333333
9250,0.0638671875
9500,0.05865885416666667
9750,0.0591796875
10000,0.05755208333333333