Year	Percent change (Units)
1980	-5.323
1981	4.673
1982	1.514
1983	6.884
1984	4.320
1985	-2.042
1986	33.202
1987	18.094
1988	13.223
1989	15.818
1990	13.435
1991	19.984
1992	4.817
1993	6.744
1994	23.936
1995	22.030
1996	14.136
1997	2.362
1998	-24.219
1999	24.635
2000	22.093
2001	-3.462
2002	14.891
2003	10.479
2004	12.084
2005	7.753
2006	12.472
2007	11.383
2008	3.263
2009	-6.908
2010	17.510
2011	14.512
2012	2.568
2013	1.640
2014	1.263
2015	2.113
2016	5.175
2017	8.857
2018	1.713
2019	-1.909
2020	-3.128
2021	10.095
2022	3.540
2023	3.088
2024	3.896
2025	3.379
2026	3.354
2027	3.215
2028	3.143
2029	3.124