Year % of total reserves 1990 119.5911741235834 1991 101.86291005058308 1992 100.64462103566706 1993 87.55959874516378 1994 87.30094878042534 1995 92.43689784151456 1996 79.57256009367478 1997 78.67317608375281 1998 67.61212087312593 1999 59.80071025350797 2000 57.19851740663488 2001 44.00994631406067 2002 38.76279458328035 2003 36.63757762556106 2004 34.965139825780106 2005 32.998561888652965 2007 27.093581676945664 2017 39.197493339814734 2020 30.968987719654642 2021 29.63743049959968 2022 37.10583886311016