re: 1 in 8 white Louisianians has black ancestry, highest percentage in country

It means of 2,048 ancestors (11 generations back), maybe less if there were some cousins remarrying, 1 in 8 Louisianians who would have one of these ancestors or more are either unaware of their sub-saharan African ancestry, because it is so marginal self report as white, or because it is rather significant still prefer identifying as white.