Year	Percent change (Units)
1980	-2.222
1981	-9.318
1982	-22.807
1983	12.987
1984	2.011
1985	0.563
1986	-2.801
1987	0.000
1988	29.792
1989	-4.361
1990	-7.248
1991	21.704
1992	2.213
1993	6.831
1994	2.112
1995	13.212
1996	-10.172
1997	21.844
1998	-1.803
1999	5.107
2000	14.033
2001	4.774
2002	1.236
2003	4.136
2004	0.811
2005	2.961
2006	9.043
2007	8.934
2008	-6.428
2009	-12.447
2010	7.943
2011	3.673
2012	0.988
2013	6.763
2014	-1.244
2015	13.265
2016	3.618
2017	-0.761
2018	4.285
2019	0.923
2020	-11.853
2021	29.870
2022	0.227
2023	0.211
2024	4.677
2025	3.018
2026	3.098
2027	3.513
2028	3.218
2029	3.200