Most domestic cats are probably 'put to sleep', by their owners, when they seem to be struggling with their infirmities. So they're not found dead anywhere.
I've seen quite a few dead cats in gardens but it's unclear whether they've died of natural causes or whether they've struggled there are being hit by a car.
One of my cats was obviously dying for several weeks but the vet said that he wasn't actually suffering to any great extent, so it would be OK to let him go in his own time. He explored all of his favourite places for a week or two and then, one night, curled up on my knee for what was obviously the last time. (He definitely didn't seek to hide anywhere). I stroked him until the early hours of the morning and then very gently lifted him up and placed him on my warm chair (which was one of his favourite places to curl up) when I went to bed. When I came down in the morning I knew that he's be dead (as he was) but he'd died peacefully, where he was obviously happiest.
Chris