Histogram relative computation

[michalRajcan]

Is your feature request related to a problem? Please describe.
While fetching detials from an app, histogram value does not show any data.
Google changed the way how they show the amount of stars people gave to an app. This causes the histogram dict to be None or contain None values.
Before they used to put precise numbers for each rating, but now they put only the relative size of a column (e.g. 27%). This can be bypassed with simple relative computation from the column sizes.

Describe the solution you'd like
Compute approximate values for each rating from the relative size of the columns (by given percentage size). This will give number of votes with maximal deviation from real results of 1% of reviews

Describe alternatives you've considered
There does not seem to be any alternative with the data given by Google.

Additional context
I have already prepared methods to compute the histogram, just need a permission to create branch and Pull request