Year	Percent change (Units)
1980	39.683
1981	5.420
1982	4.474
1983	-3.430
1984	9.493
1985	10.818
1986	4.721
1987	-27.445
1988	-10.147
1989	17.943
1990	18.561
1991	-2.239
1992	29.847
1993	-0.550
1994	26.015
1995	10.848
1996	9.010
1997	14.636
1998	15.992
1999	-2.430
2000	-5.727
2001	6.062
2002	6.303
2003	9.717
2004	3.989
2005	-37.573
2006	48.860
2007	115.961
2008	-7.003
2009	-0.970
2010	2.578
2011	6.097
2012	3.022
2013	18.848
2014	17.261
2015	15.547
2016	6.200
2017	-0.348
2018	-0.005
2019	5.958
2020	-47.555
2021	74.218
2022	10.223
2023	-0.986
2024	5.373
2025	16.963
2026	6.891
2027	6.643
2028	5.441
2029	5.758