If you look at the second reply here you’ll see some of the statistics you want, of what seems to be the Joyo Kanji list, ショウ is the most common reading, 77 characters have it, コウ is the second most common.
If you look at the second reply here you’ll see some of the statistics you want, of what seems to be the Joyo Kanji list, ショウ is the most common reading, 77 characters have it, コウ is the second most common.