Year	Percent change (Units)
1980	-1.303
1981	15.690
1982	2.809
1983	6.228
1984	8.000
1985	7.400
1986	4.800
1987	-42.196
1988	0.000
1990	10.606
1991	7.372
1992	-9.472
1993	6.843
1994	3.232
1995	10.664
1996	4.451
1997	13.462
1998	17.697
1999	6.034
2000	-0.451
2001	-6.378
2002	-7.098
2003	-8.147
2004	13.888
2005	19.400
2006	13.402
2007	17.650
2008	21.092
2009	-1.716
2010	-5.937
2011	-1.808
2012	2.656
2013	-0.279
2014	5.328
2015	18.136
2016	8.126
2017	0.980
2018	-0.664
2019	2.369
2020	-1.682
2021	-1.519
2022	1.913
2023	-17.035
2024	8.778
2025	0.266
2026	12.654
2027	11.869
2028	11.734
2029	9.904