How many 78s from 99 to 100?

Aight:

exp(char_level,map_level)

exp(lv96,77) = [101/101+181]^1.5 = 0.2143 ->21%
exp(lv96,78) = [101/101+130]^1.5 = 0.2891 ->29%

exp(lv99,77) = [104/104+401]^1.5 = 0.10 ->10%
exp(lv99,78) = [104/104+316]^1.5 = 0.123 ->12%

So EXP from 96 im comparison to 99 is arround halved.
From 96 to 97 it took me arround 130 maps (i made a maplog and playing solo), which means i would need arround ~300 maps.