2010 began the decade
Back to school, youngster.
January 1, 2001 was the first day of the new Millenium -- never mind what the unwashed around the world celebrated.
1/1/2001 was also the first day of a new decade...which ended December 31, 2010.
(Need to count it out? One, two, three, four...eight, nine, TEN.)
Therefore, 2011 -- this year -- is the first year of the latest decade.
... of the new decade.