There is general agreement that worldwide 8% of men and 0.5% of women have a red/green type of colour vision deficiency.
[…]
The 8% of colour blind men with inherited colour blindness can be divided approximately into 1% deuteranopes, 1% protanopes, 1% protanomalous and 5% deuteranomalous
the thing here is even 8% is the total number of CVD men, that’s inherited. there’s also CVD that comes with age:
… as many as 3% of the population could be affected because age-related deficiency is relatively common in the over 65s and therefore on the increase in the UK due to the rising numbers of elderly people per capita
so that’s more people. added to the 4.25% that would make 7.25% – somewhere between 1 in 13 to 14 people. doesn’t matter too much, it is significant and should be considered in design.
colorblindawareness.org seems to say it both ways
the thing here is even 8% is the total number of CVD men, that’s inherited. there’s also CVD that comes with age:
so that’s more people. added to the 4.25% that would make 7.25% – somewhere between 1 in 13 to 14 people. doesn’t matter too much, it is significant and should be considered in design.