Year	Percent change (Units)
1980	-15.197
1981	-21.860
1982	-14.705
1983	12.909
1984	-11.144
1985	-6.582
1986	-16.000
1987	1.700
1988	-5.457
1989	-0.715
1990	56.947
1991	-12.212
1992	20.974
1993	20.939
1994	-6.164
1995	28.520
1996	-6.080
1997	27.637
1998	-4.763
1999	-1.839
2000	11.858
2001	-4.222
2002	2.605
2003	-0.471
2004	7.597
2005	29.697
2006	16.574
2007	18.423
2008	6.282
2009	-9.296
2010	13.993
2011	10.289
2012	-3.100
2013	2.924
2014	-1.681
2015	3.075
2016	-1.001
2017	6.013
2018	-1.651
2019	1.418
2020	-17.392
2021	24.660
2022	-2.350
2023	-3.342
2024	1.977
2025	2.455
2026	2.534
2027	3.142
2028	3.739
2029	3.735