[quote=@Hael]
<Snipped quote by Willy Vereb>

Fair enough, but it's still a decent defense for the tech we're using. And besides, I imagine not everyone would risk those odds if it wasn't a really dire situation. 
[/quote]Yup, enough for a deterrent and percentages are a bit better if the air forces stay longer (unlike the V-1 which is pretty much a suicide bomb).
Kamikaze pilots against naval ships also suffered huge loses so the interception isn't particularly bad when somebody steers the vehicle straight for the AA defenses.

But well, after the invention of the atomic bomb nations literally could no longer allow even a single aircraft or cruise missile to pass through.
Seriously, imagine these percentages if the V1s were armed with something like the W7 nuclear warhead. London and most of Britain's important cities would've been history.