Year % of total reserves 1970 0 1971 0 1972 0.02791131785247932 1973 0.09980664950748122 1974 1.5178290921708975 1975 2.26481923670306 1976 0 1977 248.3519218330364 1978 294.8289657492223 1979 172.2334789747727 1980 134.83198238263208 1981 260.64836097666813 1982 500.1700356048456 1983 196.61729392619046 1984 622.0741686735201 1985 384.0053733761576 1986 1129.029713930726 1987 979.1160210866572 1988 434.6010237914971 1989 652.2368123370635 1990 2524.5512709993404 1991 1800.2440274378002 1992 2619.5241823027122 1993 6334.357347168357 1994 5126.408245659016 1995 6444.432811318481 1996 8763.130025338663 1997 13391.987325175356 1998 13164.834972857276 1999 9127.009332010342 2000 555.8167325418174 2001 271.76419652466535 2002 114.95720604103903 2003 55.29188101738093 2004 65.04153606806081 2005 34.60162867343026 2006 28.413220002004874 2007 8.100703799365125 2008 1.2960289044583522 2009 0.06908993981503128 2010 0.23825229806711912 2011 2.125947825236169 2012 4.649611513120053 2013 12.745450388536153 2014 5.584546012210375 2015 8.45109393760979 2016 11.792805841680533 2017 16.504423723938576 2018 12.525489905282164 2019 10.141036034159749 2020 9.294119553211004 2021 15.173799809820403 2022 17.11517291740345