Sorry, but I'm not buying the argument that the decade ends at the end of '10 because we didn't start with a zero.  The fact is that when the Catholic church calculated the years back to the birth of Christ, they went backwards from around 450 AD.  In the process, they made a mistake and forgot to figure in a 4 year reign of a minor Roman emperor.  As a result, Christ was actually born in 4 BC.  Had the mistake not been made at the time, the year would be 2014 now. 

The point I am making is we had a mistake at the beginning, which threw everything off, so it doesn't matter if we included the zero in the beginning or not.  It's just easier to go from 1/1/2000 to 12/31/2009.