Year	Percent change (Units)
1980	13.453
1981	10.338
1982	4.589
1983	4.113
1984	8.165
1985	1.867
1986	2.808
1987	2.246
1988	4.191
1989	2.817
1990	5.790
1991	6.528
1992	6.491
1993	3.154
1994	5.213
1995	1.637
1996	1.954
1997	3.762
1998	0.756
1999	3.527
2000	3.749
2001	2.163
2002	3.111
2003	2.304
2004	3.855
2005	1.426
2006	1.499
2007	3.835
2008	1.962
2009	1.773
2010	2.135
2011	4.379
2012	1.604
2013	-1.138
2014	-0.883
2015	-0.490
2016	0.101
2017	-0.392
2018	1.019
2019	0.709
2020	-0.813
2021	4.819
2022	7.573
2023	1.951
2024	2.000
2025	2.000
2026	2.000
2027	1.900
2028	1.900
2029	1.900