Year	Percent change (Units)
1980	-5.000
1981	-3.300
1982	-21.500
1983	-17.400
1984	30.400
1985	-14.500
1986	-25.700
1987	16.800
1988	2.100
1989	-5.600
1990	12.900
1991	-14.257
1992	42.589
1993	-23.320
1994	-19.574
1995	15.717
1996	11.645
1997	39.356
1998	-15.434
1999	56.080
2000	1.023
2001	2.037
2002	5.055
2003	32.941
2004	-3.648
2005	37.829
2006	-0.305
2007	42.744
2008	36.437
2009	19.010
2010	-31.781
2011	8.721
2012	20.430
2013	12.259
2014	10.081
2015	-17.750
2016	-35.016
2017	6.455
2018	5.906
2019	-7.868
2020	-33.011
2021	7.451
2022	37.273
2023	-16.643
2024	-5.753
2025	1.630
2026	0.986
2027	-1.813
2028	-0.687
2029	-1.266