What percentage of the population is rh negative recessively?

The formula is simple:

If the

frequency of the rh negative allele is x

then:

the frequency of rh negative homozygotes is x²,

the frequency of rh positive homozygotes is (1-x)²

and

the frequency of rh positive heterozygotes is 2x(1-x)

Example: Much of Central/Western/Northern Europe

frequency of the rh negative allele is 0.4

then:

the frequency of rh negative homozygotes is 0.16 (16%)

the frequency of rh positive homozygotes is 0.36 (36%)

and

the frequency of rh positive heterozygotes is 0.48 (48%)