Year	Percent change (Units)
1980	70.034
1981	19.355
1982	-16.713
1983	9.791
1984	0.481
1985	8.126
1986	-21.648
1987	0.347
1988	-8.966
1989	-23.834
1990	-6.412
1991	20.783
1992	13.992
1993	-11.175
1994	14.000
1995	11.681
1996	14.011
1997	29.095
1998	6.880
1999	18.596
2000	-6.134
2001	-0.832
2002	4.038
2003	1.835
2004	8.308
2005	8.709
2006	21.628
2007	12.255
2008	9.668
2009	-8.980
2010	13.583
2011	11.081
2012	7.098
2013	-2.644
2014	7.800
2015	14.109
2016	5.280
2017	3.763
2018	-15.577
2019	-3.233
2020	5.000
2021	17.001
2022	5.028
2023	9.462
2024	7.659
2025	5.339
2026	6.148
2027	4.820
2028	4.800
2029	4.857