As it seems you haven't grasped the sense of the lines you quoted, the point is in fact that the article is about DSLR sale decline, though it's not clear if the figures refer to that or to camera sales in total.
Something being easy doesn't make it correct, by the way.
Here are some definite numbers to work with:
a) From the latest CIPA numbers
(till Sep 2013) and Nikon's Nov 2013 financial report
, 7,481,644 DSLRs were shipped in the period Mar-Sep 2013, of which 2,980,000 (39.8%) came from Nikon. Most of the remaining 60.2% of shipped DSLRs probably came from Canon since we do not expect Pentax and Sony to sell many DSLRs. That gives us a hint of Canon's market shares in the DSLR arena for the period Mar-Sep 2013.
b) In the period of Jan-Sep 2013, for every MILC shipped worldwide, 4.66 DSLRs were shipped.
c) Thom Hogan just posted his latest analysis/prediction of the market here
based on Nikon's financial report. He translated Nikon's forecast of 6.2 mil interchangeable lens cameras (DSLR + MILC) into 33.1% market shares.Canon expects
to sell 8 mil interchangeable lens cameras which is equivalent to 42.7% market shares based on Thom Hogan's analysis. Total Canikon market shares add up to 75.8%, consistent with 2010, 2011 and 2012 numbers.