You start counting from 1 not zero
1,2,3,4,5,6,7,8,9,10
not 0,1,2,3,4,5,6,7,8,9
2010 is the 10th year of 2000
2011 is the first year of 2010
2020 is the 10th year of 2010
201(1) = 1
201(2) = 2
201(3) = 3
the decade is complete at the end of 2020
2021 you start count at 1
So the year 2030 will be apart of the 2020s? OK breh

2010s - Wikipedia
The 2010s (pronounced "twenty tens" or "two thousand (and) tens"[1][2]) was a decade of the Gregorian calendar that began on 1 January 2010, and ended on 31 December 2019.



Damn shame.

"That's nice now get back to work Hattie Mae"