Year % of total reserves 1990 269.920348323544 1991 174.71311111388016 1992 390.8778170001834 1993 352.9486198863636 1994 242.95054548557263 1995 107.91105749300813 1996 59.79256390463272 1997 15.59964922585876 1998 16.351697802272945 1999 27.781162916458563 2000 23.633039760262527 2001 11.598696239043743 2002 7.382692493008837 2003 4.3978724161076554 2004 5.273052765012996 2005 5.376764689000934 2006 4.315886757270076 2007 5.368421474835964 2008 4.825303602460478 2009 7.256155522269005 2010 2.091281684630073 2011 2.900994469730469 2012 2.272041222454545 2013 4.854105009752013 2014 7.2422682053679095 2015 20.812109934875377 2016 27.744933837426228 2017 40.00592266385163 2018 12.132557415001473 2019 25.81559477263618 2020 47.39703343873868 2021 28.02150526719349 2022 39.90362751898187