Self Publisher market share check up

My current prediction is that self published authors are at 30% market share for December 2011 (the latest there is data). This is baed off a straight line approximation from a mere two data points: 1. December 2009, I found a link (not finding it right now) where 'Boutique authors' were 10% of the market. 2. I scanned the Amazon lists in December 2010 and estimated indie authors were 20% to 33.3% of the ebook market. I took the 20% number. By definition, that is 10% growth per year (if its linear). So lets see, is there any information out there? One British link puts it 'as much as 25%.' (Note: By number of books) So testing my hypothesis: 1. The UK Amazon store is 'younger' than the US store, So Indie author penetration should be about 18 months to two years behind the US. 2. One year is 10% market share (by dollars)... So this implies the US market is about 45% Indie market share (by books)! Now the problem is, my numbers are by dollars. Since big6 books sell at higher prices, we could very well be at 30% Indie author market share (by dollars). So my admittedly simple estimate looks to be on track. The question is, what is the breaking point point? When is Indie ebooks such a large fraction of the market that the big6 loose 'economy of scale?' I doubt for a few years. Is it any wonder they make tons of noise about Amazon? Got Popcorn? Neil