Year	Percent change (Units)
1981	7.262
1982	4.281
1983	2.969
1984	2.799
1985	1.650
1986	-0.313
1987	-0.500
1988	1.205
1989	1.290
1990	4.676
1991	4.110
1992	1.701
1993	1.534
1994	1.965
1995	1.008
1996	1.908
1997	2.189
1998	1.494
1999	2.027
2000	3.075
2001	5.281
2002	3.298
2003	1.590
2004	1.243
2005	1.959
2006	1.713
2007	1.582
2008	1.658
2009	0.694
2010	1.806
2011	2.451
2012	3.305
2013	1.300
2014	-0.140
2015	0.452
2016	0.760
2017	1.200
2018	1.804
2019	2.696
2020	0.872
2021	6.395
2022	11.026
2023	0.999
2024	2.505
2025	1.981
2026	2.000
2027	2.000
2028	2.000
2029	2.000