Horizontal defrosters rare? I would have guessed that 90% or more had the horizontal style (US cars of course). Just based on the cars I see around here.
I didn't know the vertical types existed until my sister brought one home. Never seen them before, or at least never noticed. Haven't seen another in person since.

__________________
1971 280 SEL
1981 Volvo 242Tic | 1980 Bertone Coupe