Year	constant 2015 US$
1970	3265.655022426623
1971	3615.823361881489
1972	3661.398562409444
1973	3329.5710503678147
1974	2864.68396792843
1975	2206.0999332063266
1976	2337.1014524493885
1977	2601.094373199076
1978	2749.2112735737137
1979	2954.8532273492433
1980	3086.4033195290212
1981	3231.33629349632
1982	3490.4221549691515
1983	2483.6908193871113
1984	2345.502456132435
1985	2269.18344048922
1986	2442.826464381495
1987	2683.7402013625524
1988	2912.4893485860007
1989	3110.429653944714
1990	3209.4026640001944
1991	3571.002486953463
1992	3986.546916863508
1993	4210.404701487257
1994	4476.025643157085
1995	5040.485667884768
1996	5317.22241287791
1997	5666.417797884564
1998	5928.822582178486
1999	5795.753563814924
2000	5942.79225538091
2001	6108.520716142706
2002	6237.704653929916
2003	6442.693271110825
2004	6765.43564127536
2005	7293.600355374468
2006	7527.360734499718
2007	8071.029054097385
2008	8127.053834716621
2009	8384.39026089163
2010	9232.663442745234
2011	9413.797425018252
2012	10332.328268175472
2013	10717.442789772129
2014	10778.746439941295
2015	11281.813072500001
2016	11117.290057293816
2017	11057.044260703453
2018	10964.98254255784
2019	11083.413917989907
2020	9910.271304513222
2021	10423.314535487474