Consider a simple view scheme Genre / Album
How to get a summary of album subtotals per genre ?
So you can see those subtotals along side the genres, maybe even sort them in ascending/descending order.
While playing around with column groupings in the viewscheme and Details, it appears that [Track #] is the only field that is totalled whilst other numeric fields are averaged. So if the viewscheme is set to display only 1 track/Album then the [Track #] in the groupings will display the number of items that correspond to the grouping selected
Set a limit in the viewscheme to display only 1 track /album using
~limit=-1,1,[Album]
Now pick Genre instead of Pane and MC will display groupings, if you remove the other columns leaving just Genre & Track #, you have the subtotals. Sort as desired.
To make it neater, replace Track # column in the viewscheme by a Custom field, called Subtotals, and enter [Track #] in the section that says Calculated Data, to be able to sort with it.