[Shaun]

It is very strange.

BB1: 33% of finalists are female.
BB2: 33%
BB3: 50%
BB4: 25%, finished last
BB5: 50% (25% if we're being strict)
BB6: 50%
BB7: 50%
BB8: 33% (Samanda count as one HM)
BB9: 40%
BB10: 20%
BB11: 20%
BB12: 50%
BB13: 40%

CBB1: 33%
CBB2: 33%
CBB3: 33%
CBB4: 33%
CBB5: 33%
CBB6: 20%
CBB7: 20%
CBB8: 29%
CBB9: 40%

BBCH: 33%

Never been in the majority, ever.
Unless you count Teen BB which had 60% of finalists female, but that was a different format.