Looking at 2018
3 of 2018 Black last year went to purple and they selected 5 new girls-who knows where they are from but they can't be too bad to make black. The rest of Black is the same.

For 2018 purple, 11 stayed on purple, 3 moved to purple from black, and 10 new girls were selected. Two girls also moved from purple to white and 4 girls did not come back.