Year	Percent change (Units)
1980	17.143
1981	10.854
1982	28.629
1983	41.318
1984	29.373
1985	-3.530
1986	7.594
1987	-1.369
1988	-3.200
1989	17.963
1990	4.081
1991	19.019
1992	4.946
1993	10.154
1994	-6.744
1995	14.729
1996	0.003
1997	47.146
1998	1.047
1999	19.023
2000	-2.651
2001	20.424
2002	36.115
2003	-15.804
2004	-5.593
2005	16.097
2006	2.291
2007	-8.013
2008	-3.902
2009	-9.501
2010	-2.083
2011	9.141
2012	14.667
2013	6.788
2014	-2.998
2015	31.850
2016	-4.203
2017	11.022
2018	-0.762
2019	3.983
2020	-12.861
2021	3.128
2022	10.180
2023	1.769
2024	3.048
2025	3.533
2026	3.099
2027	4.986
2028	3.430
2029	3.488