Year	Percent change (Units)
1980	2.834
1981	5.442
1982	-12.922
1983	23.600
1984	1.021
1985	-8.187
1986	4.958
1987	27.063
1988	32.747
1989	21.581
1990	23.682
1991	12.950
1992	8.968
1993	11.778
1994	15.749
1995	19.968
1996	-0.605
1997	-11.298
1998	-21.647
1999	10.489
2000	27.118
2001	-5.496
2002	6.221
2003	11.096
2004	20.305
2005	16.190
2006	2.943
2007	4.200
2008	11.399
2009	-20.772
2010	22.956
2011	12.400
2012	5.629
2013	1.681
2014	-5.298
2015	0.004
2016	-0.992
2017	6.227
2018	8.274
2019	-5.167
2020	-13.911
2021	17.771
2022	3.610
2023	-2.673
2024	4.534
2025	4.217
2026	3.382
2027	3.344
2028	3.069
2029	3.281