Year	Percent change (Units)
1980	17.207
1981	17.450
1982	7.228
1983	5.458
1984	2.702
1985	2.079
1986	1.154
1987	2.939
1988	0.298
1989	2.645
1990	7.250
1991	5.922
1992	3.805
1993	4.260
1994	0.395
1995	2.391
1996	4.413
1997	0.499
1998	2.105
1999	1.013
2000	0.193
2001	1.876
2002	0.748
2003	0.125
2004	2.853
2005	3.446
2006	3.017
2007	6.995
2008	10.123
2009	0.373
2010	0.761
2011	3.186
2012	2.598
2013	0.805
2014	0.194
2015	-1.726
2016	-0.158
2017	2.153
2018	2.324
2019	0.906
2020	-0.606
2021	1.557
2022	5.660
2023	4.571
2024	2.955
2025	1.998
2026	1.998
2027	1.998
2028	1.998
2029	1.998