hard to say..just off wikipedia...

A gold reserve is the gold held by a central bank or nation intended as a store of value and as a guarantee to redeem promises to pay depositors, note holders (e.g., paper money), or trading peers, or to secure a currency.

At the end of 2004, central banks and investment funds held 19% of all above-ground gold as bank reserve assets.[1]

It has been estimated that all the gold mined by the end of 2009 totaled 165,000 tonnes.[2] At a price of US$1900 per troy ounce, reached in September 2011, one tonne of gold has a value of approximately US$61.1 million. The total value of all gold ever mined would exceed US$10.1 trillion at that valuation.[note

[link to en.wikipedia.org]