Year	Percent change (Units)
1980	13.761
1981	9.897
1982	8.878
1983	8.518
1984	6.132
1985	4.931
1986	3.377
1987	3.622
1988	5.896
1989	7.143
1990	2.067
1991	4.550
1992	2.599
1993	2.916
1994	1.646
1995	-0.465
1996	1.726
1997	1.599
1998	0.780
1999	2.241
2000	2.869
2001	2.350
2002	1.716
2003	1.191
2004	0.147
2005	1.016
2006	1.236
2007	1.939
2008	3.381
2009	1.806
2010	2.766
2011	2.605
2012	3.449
2013	1.933
2014	0.552
2015	-0.249
2016	1.100
2017	0.505
2018	1.319
2019	1.137
2020	0.192
2021	3.164
2022	8.792
2023	1.324
2024	1.906
2025	1.984
2026	2.000
2027	2.000
2028	2.000
2029	2.000