We rolled out the Patriot when it was still in a prototype, half-baked stage in Iraq, too – just that it was all we had that might be able to intercept a ballistic missile, and we really needed the capability right then – and it didn’t fare well either.
About 9% intercept ratio during Desert Storm, which was 30 years ago, but both the Patriot and the Al Hussain missiles were pretty much brand new. S400 is a decade and a half newer than ATACMS though.
Patriot did (a lot?) better in Iraqi Freedom, but the exact numbers are all over the place.