Talk:800th page!/@comment-31513065-20191229184350/@comment-31513065-20191230045452

The first decade started at Year 1, a decade is 10 years, so the first decade was from year 1 to 10. The next was 11-20, then 21-30, then 31-40 and so on. That's why this decade is 2011-2020 and the next decade is 2021-2030.