Year	Percent change (Units)
1980	12.303
1981	5.698
1982	-6.617
1983	11.053
1984	1.494
1985	22.051
1986	123.564
1987	-41.893
1988	36.058
1989	4.848
1990	-10.515
1991	3.304
1992	1.870
1993	4.480
1994	-14.827
1995	2.316
1996	2.995
1997	12.084
1998	22.450
1999	-24.535
2000	-17.424
2001	-2.371
2002	9.007
2003	-2.257
2004	2.185
2005	1.691
2006	17.019
2007	-17.478
2008	18.342
2009	34.526
2010	-6.031
2011	7.454
2012	-3.426
2013	18.685
2014	4.044
2015	18.189
2016	6.827
2017	-11.701
2018	-15.725
2019	10.536
2020	3.872
2021	-6.569
2022	-8.744
2023	1.597
2024	9.745
2025	4.480
2026	3.294
2027	2.932
2028	2.828
2029	2.610