I don't have any percentages of top musicians and artists who did badly in school and who have/had learning disabilities. That's why I didn't give any before. But it is common. Here's a partial list of famous people with learning disabilities. A lot of them are people who were engaged in creative pursuits (and I include inventor in that category)...

http://www.greatschools.net/LD/managing/famous-people-dyslexia-ld-or-ad-hd.gs?content=696&page=3



Just for information, here's a partial list of famous people who were home schooled...

http://www.home4schoolgear.com/famoushomeschooler.html