Year	Percent change (Units)
1980	5.196
1981	3.498
1982	0.200
1983	-2.500
1984	-2.000
1985	3.600
1986	4.800
1987	-0.500
1988	1.140
1989	2.950
1990	-1.090
1991	0.040
1992	-0.250
1993	-0.180
1994	0.171
1995	5.572
1996	8.136
1997	5.723
1998	4.931
1999	1.618
2000	-2.068
2001	0.121
2002	-1.668
2003	-1.360
2004	1.232
2005	1.721
2006	1.516
2007	1.765
2008	2.543
2009	3.251
2010	2.018
2011	-4.857
2012	10.864
2013	9.272
2014	8.794
2015	8.843
2016	7.172
2017	7.412
2018	4.842
2019	6.721
2020	0.701
2021	7.062
2022	6.862
2023	6.200
2024	6.500
2025	6.400
2026	6.300
2027	6.100
2028	6.000
2029	6.000