Year	Percent change (Units)
1980	67.807
1981	-20.509
1982	-24.660
1983	-28.526
1984	14.230
1985	-19.005
1986	17.526
1987	13.253
1988	-15.310
1989	1.044
1990	-24.706
1991	104.504
1992	76.694
1993	13.423
1994	26.700
1995	-11.484
1996	19.483
1997	29.850
1998	9.510
1999	-15.904
2000	-2.344
2001	-17.128
2002	-53.197
2003	49.833
2004	50.322
2005	18.366
2006	12.754
2007	22.248
2008	14.081
2009	-23.556
2010	39.799
2011	21.489
2012	-6.062
2013	3.718
2014	-11.318
2015	3.263
2016	3.313
2017	14.692
2018	-6.795
2019	-20.724
2020	-10.257
2021	29.691
2022	10.684
2023	-2.885
2024	-16.473
2025	6.496
2026	5.266
2027	4.969
2028	4.173
2029	3.321