Year	Percent change (Units)
1980	-10.026
1981	-14.287
1982	-14.463
1983	-6.916
1984	23.363
1985	-20.083
1986	18.074
1987	-11.234
1988	12.442
1989	2.126
1990	12.195
1991	-4.644
1992	-20.676
1993	13.424
1994	-14.506
1995	-11.827
1996	7.838
1997	38.611
1998	29.725
1999	14.767
2000	5.270
2001	-5.820
2002	4.864
2003	-8.731
2004	25.820
2005	9.318
2006	16.041
2007	14.713
2008	15.792
2009	2.731
2010	31.103
2011	18.674
2012	11.383
2013	3.420
2014	1.985
2015	-2.830
2016	-3.990
2017	0.626
2018	4.755
2019	0.227
2020	-0.165
2021	-2.356
2022	8.256
2023	-0.561
2024	-2.413
2025	3.741
2026	10.075
2027	13.704
2028	4.430
2029	0.596