Year	Percent change (Units)
1980	59.145
1981	75.433
1982	64.460
1983	111.149
1984	110.209
1985	163.398
1986	77.921
1987	85.846
1988	666.955
1989	3398.272
1990	7481.691
1991	409.529
1992	73.529
1993	48.580
1994	23.734
1995	11.131
1996	11.549
1997	8.547
1998	7.255
1999	3.469
2000	3.759
2001	1.975
2002	0.192
2003	2.261
2004	3.662
2005	1.618
2006	2.001
2007	1.779
2008	5.788
2009	2.935
2010	1.529
2011	3.369
2012	3.656
2013	2.807
2014	3.245
2015	3.548
2016	3.593
2017	2.804
2018	1.317
2019	2.136
2020	1.827
2021	3.979
2022	7.871
2023	6.269
2024	2.328
2025	2.009
2026	2.018
2027	2.018
2028	2.018
2029	2.000