Year	Percent change (Units)
1980	6.170
1981	-0.771
1982	-4.667
1983	5.691
1984	10.050
1985	6.156
1986	-2.911
1987	5.447
1988	10.400
1989	10.158
1990	7.980
1991	5.114
1992	2.116
1993	-5.489
1994	10.332
1995	5.905
1996	8.642
1997	7.270
1998	5.758
1999	4.064
2000	10.186
2001	5.192
2002	0.291
2003	3.507
2004	7.975
2005	5.455
2006	5.855
2007	5.635
2008	0.954
2009	-11.899
2010	11.970
2011	5.954
2012	0.924
2013	0.694
2014	2.957
2015	3.630
2016	3.726
2017	5.289
2018	5.348
2019	2.248
2020	-10.020
2021	14.328
2022	7.879
2023	-1.681
2024	1.831
2025	3.473
2026	3.084
2027	2.286
2028	2.347
2029	2.335