7% is the going rate. But who knows what arrangements are made privately. The shot glass is a joke of course; Stevie's got more money than a lot of players.
Actually the % earned is generally based on how the player finishes in the tournament. If a player wins, his caddy earns 10%, if he finished in the top 5 or 10 (not sure) its about 7%, below that its 5%. I believe caddies are also payed either a salary, or fee per tourny on top of the % of winnings.
My mom caddied for Glen Hnatiuk in a Nike Tour event years ago. He made the cut and she had to pack his huge bag around all four days. In the end he gave her a dozen of his used balls.
A few years back, not long ago, Steve Williams was listed as the highest paid athlete in New Zealand. The shot glass story is very apropo.
Interesting story about Hnatiuk. A couple of years ago, GOLF Mag ran a piece on inside dirt from unanamed caddies. Comments such as "David Frost used to get angry at people for breathing his air" were the norm. I'm waiting for the complete tell all book from a caddie or two.