Year	Percent change (Units)
1980	-17.031
1981	-24.300
1982	7.300
1983	-15.400
1984	25.200
1985	0.300
1986	34.500
1987	4.700
1988	38.300
1989	8.000
1990	29.200
1991	2.000
1992	-10.893
1993	28.758
1994	9.382
1995	54.704
1996	-13.121
1997	-11.415
1998	-8.158
1999	-24.737
2000	-9.230
2001	-26.807
2002	-21.170
2003	-1.289
2004	15.712
2005	6.616
2006	14.874
2007	19.803
2008	20.482
2009	-22.578
2010	29.598
2011	15.483
2012	-11.385
2013	15.196
2014	-7.727
2015	-14.973
2016	1.458
2017	9.025
2018	-0.497
2019	-11.670
2020	-11.972
2021	2.386
2022	-8.533
2023	37.825
2024	0.985
2025	1.779
2026	1.898
2027	1.818
2028	1.584
2029	1.420