Most of western central banks vaults are nearly empty
The paces of physical drainage from west to east have been escalated; most of western central bank vaults are nearly empty, including Canadian CB whose gold and silver reserves can be manually counted by ounces. Germany has to wait for 10 years for a merely 350 tons of their gold to be returned from the now virtually empty Fort Knox. Ukraine's gold has been quickly liberated to US (probably to Yellen's coffer). With Russia, China, and Iran are on full-frontal assault the depleted physical markets, the physical constraints can be easily pushed forward in matter of days or weeks.
Gold is potentially a dangerous commodity to central banks. They need to control the price of pm's to show currency stability and credit rating. The Federal Reserve has not owned any gold for 80 years.
Silver is considered a strategic metal by the US government, and it does not disclose its reserve.
If central banks horded metals, the price would be much higher. When some big investors come along, the metals may begin a move in earnest.