The percentage of adults approving of marriage between Black and white people went from 4% in 1958 to 94% in 2021, per the Gallup poll. In 1967, 16 states had anti-miscegenation laws, the year in which the Supreme Court banned these laws in Loving v. Virginia.
This change in opinion took time among older people., For people 50 or older in 1991, only 27% approved vs 91% in 2021 (when 98% of persons 18-29 approved).
The chart below shows the change in support by region of the country. Note how the South lagged and the West led, with the entire country uniformly in very high approval in 2021