Year	current US$
1970	570
1971	620
1972	700
1973	870
1974	1050
1975	1200
1976	1260
1977	1390
1978	1590
1979	1850
1980	2160
1981	2300
1982	2270
1983	2100
1984	2020
1985	1950
1986	2130
1987	2520
1988	2840
1989	2900
1990	3010
1991	2910
1992	3310
1993	3660
1994	4030
1995	4250
1996	4370
1997	4400
1998	4410
1999	4490
2000	4620
2001	4790
2002	5290
2003	6630
2004	8650
2005	10380
2006	11240
2007	11770
2008	13250
2009	13410
2010	13260
2011	13250
2012	13080
2013	13520
2014	13560
2015	13230
2016	13100
2017	13180
2018	14980
2019	16570
2020	16040
2021	17740
2022	19050
2023	19820