Year	Percent change (Units)
1980	-20.921
1981	-10.151
1982	-3.126
1983	5.579
1984	10.343
1985	-22.469
1986	-4.591
1987	-15.943
1988	-7.020
1989	13.665
1990	44.265
1991	-8.034
1992	-24.338
1993	21.961
1994	16.414
1995	-13.359
1996	60.396
1997	9.954
1998	-5.587
1999	0.126
2000	21.664
2001	-2.997
2002	-20.222
2003	16.186
2004	84.855
2005	10.266
2006	2.585
2007	6.197
2008	-5.962
2009	10.603
2010	13.321
2011	12.855
2012	4.946
2013	5.494
2014	8.606
2015	1.391
2016	6.972
2017	3.945
2018	14.882
2019	8.627
2020	-8.049
2021	3.157
2022	10.968
2023	-3.176
2024	17.215
2025	19.957
2026	12.245
2027	7.389
2028	8.874
2029	5.888