Year	Percent change (Units)
1980	15.109
1981	69.772
1982	28.771
1983	6.500
1984	24.800
1985	13.400
1986	-5.700
1987	23.600
1988	12.094
1989	-3.658
1990	-2.302
1991	6.050
1992	5.562
1993	6.384
1994	14.858
1995	6.455
1996	9.634
1997	19.063
1998	9.731
1999	2.922
2000	11.522
2001	22.158
2002	15.806
2003	12.526
2004	13.681
2005	10.286
2006	12.302
2007	11.507
2008	6.593
2009	-7.758
2010	11.434
2011	6.337
2012	16.214
2013	-0.901
2014	4.307
2015	2.617
2016	3.822
2017	8.284
2018	4.967
2019	6.534
2020	-5.159
2021	21.317
2022	3.352
2023	-9.491
2024	15.212
2025	3.828
2026	2.332
2027	3.148
2028	3.121
2029	3.139