If you’re just counting the math yes, but really that makes for inconvenient definitions, that makes the 1970 part of the 60s, and 2000 part of the 1900s and that’s just goofy. I say the first decade/ century/ millennium got short sheeted a year so that 2010 is the beginning of the 2010s.
The 60’s run from 1960 to 1969. The 70’s, in your example, ran from 1970 to 1979.