Year	current US$
1970	1761.3835796701017
1971	2033.9707612795685
1972	2497.4177910863327
1973	3332.0987124018025
1974	3957.5241919228856
1975	4500.816851609607
1976	4855.45655602095
1977	5800.345868996318
1978	6956.923371742557
1979	8311.172614664163
1980	9175.135293700692
1981	7864.491314587043
1982	7896.856164853264
1983	8040.735666274077
1984	7571.9674991993315
1985	7740.789041420875
1986	11018.27676093323
1987	13792.323979007699
1988	14880.06436797592
1989	14792.558032793202
1990	18400.430061269497
1991	18906.06152022472
1992	20999.647418165372
1993	20251.09894117043
1994	21546.584564018834
1995	25386.488727794876
1996	25025.553419868684
1997	22282.145263577208
1998	22789.998689281114
1999	22355.194500153775
2000	20391.623865178666
2001	20142.909992594774
2002	21920.521977530196
2003	26718.418439689325
2004	30611.249197044017
2005	31858.616035150586
2006	33992.18043447067
2007	39159.00577630789
2008	43635.109927905505
2009	39649.39482369938
2010	39022.256155235715
2011	42625.237354532954
2012	39980.63083928868
2013	41694.07140868683
2014	42465.76660557938
2015	35811.6857751508
2016	37196.16774742248
2017	38441.73271854942
2018	41651.80739037021
2019	40712.57534124936
2020	39515.55740699578
2021	43281.73347974614