Year	Percent change (Units)
1980	21.355
1981	16.244
1982	9.607
1983	6.242
1984	12.250
1985	11.382
1986	11.544
1987	28.137
1988	29.468
1989	84.463
1990	40.656
1991	34.205
1992	31.423
1993	38.122
1994	60.817
1995	59.923
1996	99.876
1997	50.040
1998	35.782
1999	23.570
2000	16.206
2001	12.531
2002	22.434
2003	31.091
2004	21.747
2005	15.955
2006	13.663
2007	18.699
2008	31.441
2009	26.041
2010	28.187
2011	26.090
2012	21.069
2013	40.639
2014	62.169
2015	121.738
2016	254.949
2017	438.117
2018	65374.082
2019	19906.024
2020	2355.147
2021	1588.513
2022	186.542
2023	337.458
2024	99.981
2025	150.000