Year U.S. dollars (Units) 1986 26.842 1987 17.871 1988 34.048 1989 41.457 1990 104.240 1991 225.192 1992 263.638 1993 253.183 1994 276.757 1995 333.643 1996 330.146 1997 315.505 1998 279.689 1999 306.664 2000 313.224 2001 345.368 2002 368.731 2003 406.869 2004 465.695 2005 550.210 2006 639.874 2007 763.623 2008 903.246 2009 912.750 2010 992.085 2011 1133.384 2012 1241.402 2013 1356.991 2014 1485.892 2015 1606.561 2016 1735.785 2017 1888.070 2018 2097.235 2019 2281.377 2020 2122.700 2021 2187.734 2022 2319.190 2023 2460.351 2024 2627.767 2025 2807.731 2026 3001.602 2027 3205.566 2028 3417.140 2029 3633.077