@britt I have no doubt that the Syrians and Russians combined to shoot down at least 10% of the inbound weapons of the first wave, but probably not much more than that. The first wave concentrated on SAM's and their support radars.
Open source guesswork on my part is:
1st wave 90 sea (surface and sub) launched cruise missiles and...
2nd wave: 172 air launched weapons...
For a total 262 PGM's combined.
Not counting USAF F-15's from Saudi Arabia and USAF F-16's from Turkey.