Year	Percent change (Units)
1980	-11.508
1981	4.858
1982	7.872
1983	3.003
1984	15.142
1985	14.803
1986	6.462
1987	8.861
1988	8.800
1989	9.036
1990	8.978
1991	11.427
1992	14.695
1993	12.188
1994	8.497
1995	9.461
1996	9.460
1997	6.964
1998	8.982
1999	8.072
2000	-7.322
2001	-8.838
2002	2.737
2003	2.971
2004	3.637
2005	5.400
2006	3.100
2007	4.300
2008	6.000
2009	7.200
2010	5.700
2011	9.600
2012	9.500
2013	12.900
2014	8.062
2015	4.693
2016	3.563
2017	4.994
2018	2.537
2019	2.784
2020	4.514
2021	7.390
2022	6.524
2023	3.859
2024	5.046
2025	4.126
2026	4.046
2027	3.960
2028	3.960
2029	3.960