Year	Percent change (Units)
1980	9.209
1981	2.730
1982	19.689
1983	28.116
1984	6.795
1986	-6.041
1987	-4.168
1988	-3.508
1989	23.706
1990	-0.292
1991	-3.931
1992	4.831
1993	-17.073
1994	-7.620
1995	5.501
1996	6.483
1997	14.277
1998	11.439
1999	8.094
2000	-5.274
2001	9.495
2002	-3.308
2003	-5.228
2004	12.120
2005	-10.677
2006	-1.272
2007	20.225
2008	-4.454
2009	11.974
2010	-10.334
2011	12.847
2012	-4.366
2013	14.544
2014	15.206
2015	12.510
2016	1.091
2017	3.098
2018	-1.481
2019	-2.217
2020	-6.972
2021	4.597
2022	5.740
2023	9.306
2024	4.539
2025	7.892
2026	8.489
2027	6.086
2028	7.833
2029	7.426