Year	Percent change (Units)
1980	19.367
1981	15.125
1982	4.614
1983	1.473
1984	2.049
1985	0.503
1986	2.174
1987	7.039
1988	0.829
1989	4.395
1990	4.331
1991	5.539
1992	5.661
1993	0.775
1994	2.664
1995	5.863
1996	0.925
1997	-0.006
1998	3.202
1999	2.415
2000	4.848
2001	5.273
2002	-0.256
2003	1.034
2004	1.460
2005	3.911
2006	3.564
2007	2.823
2008	5.550
2009	-0.157
2010	3.250
2011	2.769
2012	4.178
2013	1.469
2014	3.517
2015	-0.984
2016	-3.078
2017	0.104
2018	2.555
2019	0.539
2020	-1.755
2021	2.410
2022	6.373
2023	3.651
2024	1.759
2025	1.956
2026	2.000
2027	2.000
2028	2.000
2029	2.000