This is how you "get it right." You do actual market research. And then charge $500 for the full report.
http://www.google.com/hostednews/afp...76101cbaf5.701
Readership rates:
Laptops: 35%
Kindle: 32%
iPhone: 15%
Sony: 12%
Netbooks: 10%
Nook: 9%
iPad: 9%
Other smartphones: 8%
50% of ebooks are currently bought from Amazon.
This includes multiple device use (hence the total is above 100%), and as best I can determine is US-only.
Forrester believes 7% of the US public reads ebooks, and believes this will double next year.
If you actually want to pony up for the full report, here ya go:
http://www.forrester.com/rb/Research...q/id/57664/t/2