No one knows, or will admit just how reliable the various missiles and bombs would actually be in use. No one really knows how many birds will leave the silo's or sub's and then explode, go off course or how many warheads will actually detonate or just fizzle. In a book I read there was an example of an attack on an airbase outside Berlin in the early 1960's that had it being attacked by IRBMs from the UK, then a F84 then another IRBM and then yet another airstrike by a Canberra, all in a 17 minute timespan.
I don't know if this helps you or the rest of the posters here but this is taken from Salamanders "Illustrated Guide to Strategic Weapons" . . .tbh, I have know idea where the author got his info from.
Systems deployed in late '80s and it's availability.
ICBM's
Minuteman I . . . 442 . . . . 85%
Minuteman II . . .536 . . . .85%
Minuteman III . . . .14 . . .85%
SS-11 . . . 440 . . . 85%
SS-12 . . . .60 . . . 85%
SS-17 . . . 150 . . .90%
SS-18 . . . 308 . . .90%
SS-19 . . . 360 . . .90%
SS-25 . . . .72 . . . 95%
SLBM's and their platform
Poseidon . . . 96 . . . 55% (Lafatette/Franklin)
Trident C1. . .96 . . . 55% (Lafayette/Franklin)
Trident D2 . . 120 . . 66% (Ohio)
SS-N-6 . . . 96 . . . 30% (Yankee I)
SS-N-8 . . . 82. . . .30% (Golf III/Hotel III/ Delta I/II/III)
SS-N-!7 . . .12 . . .30% (Yankee II)
SS-N-18 . . 64 . . . 30% (Delta III)
SS-N-20 . . 20 . . . 40% (Typhoon)
SS-N-23 . . 16 . . . 40% (fielded Delta IV)
Typical Assessment of Reliability of ICBM 1st RV Missile System (UNITED STATES ONLY)
1st stage motor fires successfully . . . . . . . . . . . . . . 95%
Missile leaves silo . . . . . . . . . . . . . . . . . . . . . . . . . 95%
2nd stage motor fires . . . . . . . . . . . . . . . . . . . . . . 98%
2nd stage separation . . . . . . . . . . . . . . . . . . . . . . .98%
2nd stage motor terminates correctly . . . . . . . . . . .98%
Nose shroud separates . . . . . . . . . . . . . . . . . . . . . 98%
Post-boost vehicle separates . . . . . . . . . . . . . . . . . 98%
PBV despatches all RV's correctly . . . . . . . . . . . . . 95%
RV penetrates atmosphere and arrives on target . . . 90%
Warheads detonates correctly . . . . . . . . . . . . . . . . 95%
OVERALL SYSTEM RELIABILITY . . . . . . . . . . . . . . 66%
I hope this has helped
Regards filers.