0, and we own about 15 bikes (mountain, e-bikes, folding bikes, commuting bikes)
We use heavy duty u-locks, lock the wheels with a cable, and on the e-bikes have installed motion alarms that sound if someone tries to move the bike. But honestly, I don't think anyone's attempted stealing them yet as the alarms have never gone off outside of us accidentally hitting them ... ha! We live in Provo.