The majority of real gold trading is retail I presume so it's never going to show up in any type of official metric. Still, a cool little statistic.
Here where I live every bit of sold or bought Gold by any kind of retailer, pawnshop etc, has to be noted and submitted on a monthly basis to the government due anti terrorism laws. I am however not sure whether or not this information will be used for anything other than the law's purpose.
The terrorism reason is just a smoke screen. They need to track gold ownership to know where to go, when they want to confiscate it. It's been done before and it will happen again. I think people in
Brazil are just hedging against the falling local fiat currency value, so they are just protecting their wealth. Bitcoin looks very volatile in the short term, but when you look at the long term value, it is
actually keeping it's value very well... A year ago, bitcoins sold for $200+