Answer: 50%
Explanation: Take the genotype of the woman as "aa", while the man as "Aa". Under assortment, the first filial generation gives: "aa", "Aa", "aa", "Aa".
From the genotype expressed in the F1 generation, only two of the four offsprings were homozygous and recessive; thus, albinism will only be expressed half (1/2) of the time