Year	Percent change (Units)
1980	-3.000
1981	8.000
1982	-12.900
1983	4.600
1984	12.500
1985	-5.900
1986	-33.800
1987	54.300
1988	7.000
1989	2.700
1990	14.600
1991	0.186
1992	8.359
1993	-8.275
1994	8.236
1995	12.240
1996	10.698
1997	6.020
1998	2.536
1999	1.426
2000	1.624
2001	-2.578
2002	23.562
2003	-1.931
2004	13.537
2005	28.148
2006	14.255
2007	17.501
2008	10.105
2009	-2.640
2010	-3.266
2011	-5.404
2012	3.838
2013	0.064
2014	-2.115
2015	6.721
2016	-1.971
2017	-1.252
2018	-10.725
2019	-5.927
2020	-7.342
2021	-8.558
2022	3.271
2023	-6.185
2024	2.937
2025	5.712
2026	5.817
2027	2.001
2028	2.203
2029	2.585
