Like others, I view someone that's been petrified as neither alive nor dead, their soul is in stasis and trapped in the stone.
In my world people that have been petrified ignore minor damage, so it takes a fair amount of force to break the statues. So rain and general erosion doesn't have much of an effect but a tree falling on the statue could still shatter it. If broken, the soul is released and goes on to it's final destination. Eventually all souls would probably be released, but it could take millenia.
I can see it now. Some minor afterlife clerk is doing a review of "accounts" and comes across an unusually large number of souls that based on his actuary tables should have passed on to the afterlife but they're missing. Unable to balance the books he goes to his supervisor...
Clerk: "Excuse me sir, but I can't seem to get these books to balance."
Supervisor: "What is it this time Bob, I'm quite busy judging souls here."
Clerk: "Well, sir, speaking of judging souls there seems to be a bit of a discrepency. I was expecting these souls to pass through the gates but I can't seem to find a record."
Supervisor: "And you've double checked with Shirley? Remember liches store their souls, many races have quite extensive life spans."
Clerk: "Of course sir, I, umm, won't make that mistake again. But there's a cluster of human souls around this village that should have shown up a few weeks ago. I'm afraid they may have bypassed your eminence..."
Supervisor: "Nonsense!"
Clerk: "But the numbers..."
Supervisor: "It's probably some pesky medusa again. Why don't you have that adventuring company look into it. They've been keeping my ledger quite full lately, they owe us one."
Clerk: "Yes, sir, of course sir."
Sounds like the start of an adventure!
