I don't think 95% of all jewelry is recent drops, because at least on land most people don't gold ring hunt and are either after old or new coins. I think it's only a small percentage of hunters who land hunt mostly for rings myself. For that reason I bet at some pounded out sites there are more gold rings laying around than silver left to be found. Well, maybe not, because I've read an excellent article about how even a tiny little piece of iron shallower than a coin will mask it to any detector, and often you won't even hear the null from the iron as you pass over it because it's deep and small enough to be silent, yet it is still blocking you from seeing the deeper coin. For that reason there are probably a ton of silver coins still waiting to be found at sites people have long since given up on.
But anyway, I do agree about mainly going after the shallow (say less than 4" or perhaps only as deep as 2") signals when looking for gold rings on land. Not only does it save you time, but it also prevents a lot of nasty plugs being dug in one area as you've got to dig the junk to find the gold. By going after the shallow stuff only you can use your Pro Pointer (super tune it) to find it and then a screwdriver to pop it out of the ground quickly. Not only is this a time saver, but it also means no tons of plugs all over the place for the numerous pieces of junk you have to dig in order to find the gold. In fact, in ball diamonds and other nicer areas where I might ring hunt, the only thing I'll ever use there is a screwdriver to pop targets. Something about digging numerous plugs looking for gold in a nice ball diamond or other neat little modern park square tells me I'm at risk to be banned in my areas. At least when old coin hunting at a place like that you are digging less targets, so using a digger isn't as big of a deal *at some of those sites*. Not all, though. Some I simply won't carry a digger into even after old coins. In particular real nice fenced in ball diamonds or fancy town squares.
Now, when I'm hunting older sites looking for rings, I'll often change my strategy and go deep. I find out how deep the round tabs are and then dig any foil or tab signals (or really any signal between iron and coin for that matter) that is deeper and thus older than the round tabs and other more modern junk. Even foil has a certain age where it became common and popular, just like the round tabs. Not sure when this happened with foil (?) but I often find that if I'm only digging targets deeper than the round tabs at a site I rarely find any foil deeper than that myself. So, by "traveling back in time" before round tabs and other more modern junk, I increase my odds of that deep target being at least something good, if not in fact a gold ring.
Recently a friend used this strategy. We were hunting a site where the tabs maxed out at about 5" deep. He came over with a smile on his face and a wide band man's gold ring that was cut in half and some old letters engraved on the head that you could tell meant it was old by the style of those letters. I asked what it read as and he said lower than nickle, so obviously it read as foil. I then thought for a moment and said "What possessed you to dig that signal?" He said, "Oh, it was deeper sounding then the tabs and other more modern junk we've been digging."
But, yea...at more modern sites I always keep it shallow when digging (or more likely just probing when I can) for gold rings. It also speeds up the process of digging X amount of trash until the laws of probability finally hand you that gold ring.