In 1950, only about 7% of women did this, but as of last year, it’s up to about 75%. What is it?

In 1950, only about 7% of women did this, but as of last year, it’s up to about 75%.  What is it?

In 1950, only about 7% of women did this, but as of last year, it’s up to about 75%.  What is it?

Ans: Dye their hair.