1.Global central banks have expanded their balance sheets to $19 trillion—about the size of the U.S. GDP—from about $3 trillion in 2000
http://globaleconomicanalysis.blogspot.com/2015/10/central-bank-balance-sheets-what-will.html
http://globaleconomicanalysis.blogspot.com/2015/10/central-bank-balance-sheets-what-will.html