Year	Percent change (Units)
1980	8.837
1981	5.779
1982	17.384
1983	11.707
1984	11.742
1985	13.041
1986	6.122
1987	-4.130
1988	-1.823
1989	0.449
1990	0.325
1991	-1.754
1992	-0.007
1993	-0.744
1994	32.104
1995	8.076
1996	2.835
1997	1.784
1998	0.989
1999	0.818
2000	0.754
2001	3.053
2002	2.398
2003	-0.048
2004	0.515
2005	1.707
2006	2.114
2007	5.863
2008	6.335
2009	-2.248
2010	1.228
2011	3.404
2012	1.417
2013	0.710
2014	-1.089
2015	0.858
2016	1.192
2017	1.143
2018	0.455
2019	1.020
2020	2.529
2021	2.178
2022	9.689
2023	5.947
2024	3.900
2025	2.000
2026	2.000
2027	2.000
2028	2.000
2029	1.994