Solve this logic number sequence puzzle by the correct digit 8080 = 6 1357 = 0 2022 = 1 1999 = 3 6666 = ?

This logic is about finding the number of loops or holes (or let's say circles in general) in the given values. Our guide now will be:

1 = no holes; hence 0. Same goes with 2,3,5,7

6 = 1 hole; hence 1. Same goes with 0,9

8 = 2 holes, hence 2.

I'm not sure though if the trick counts 4 as part of the "holed" group. 

Finally

8080 = 6 

1357 = 0

2022 = 1

1999 = 3 

6666 = 4 -> answer