Year	Percent change (Units)
1980	46.339
1981	-12.183
1982	-0.317
1983	-0.889
1984	-10.491
1985	50.368
1986	-12.134
1987	27.393
1988	3.162
1989	3.841
1990	-9.545
1991	-11.367
1992	-17.340
1993	1.090
1994	52.320
1995	25.873
1996	-7.502
1997	0.666
1998	53.535
1999	-25.676
2000	-5.504
2001	6.669
2002	4.520
2003	-8.666
2004	9.508
2005	7.704
2006	7.151
2007	10.718
2008	36.517
2009	3.123
2010	-1.891
2011	8.826
2012	6.249
2013	-2.132
2014	14.436
2015	11.762
2016	-5.626
2017	4.367
2018	20.605
2019	17.568
2020	-2.435
2021	-8.148
2022	-1.181
2023	21.554
2024	8.916
2025	7.330
2026	11.725
2027	-12.923
2028	15.704
2029	7.286