Year % of total reserves 1970 93.7240924937401 1971 225.75327129154502 1972 130.14242617183538 1973 49.710268464758876 1974 44.40141355776625 1975 100.09139722639273 1976 51.42901507649393 1977 70.86474634964578 1978 57.775385980800586 1979 59.441763007602965 1980 111.68842051980276 1981 258.1052672542815 1982 366.8104904216252 1983 313.8233822207869 1984 413.75082022343656 1985 143.14088516800336 1986 99.60398749317235 1987 94.61768401523815 1988 110.8664316189051 1989 264.998316462704 1990 167.7969848781439 1991 181.51723803792635 1992 141.31429905023666 1993 55.826056194579365 1994 44.80903491524481 1995 133.63925124430287 1996 119.16140167316212 1997 142.64694824988564 1998 124.5428326087661 1999 111.63198291051542 2000 112.61604363183942 2001 137.4315501126713 2002 141.38541270277113 2003 158.12546449003213 2004 135.04209749322945 2005 124.78059470454433 2006 88.22126440781899 2007 41.60562968704823 2008 41.90868098150186 2009 40.17294914725974 2010 31.438004119786733 2011 55.647133151404425 2012 58.42202788295611 2013 120.16669789771743 2014 107.8964102676788 2015 232.887650249561 2016 106.77391706824315 2017 100.3476583522164 2018 102.33872980693573 2019 149.32081444226938 2020 108.12898069318668 2021 110.89501914779952 2022 109.58738174865974