Year	Percent change (Units)
1980	-2.309
1981	1.149
1982	0.832
1983	3.438
1984	-0.983
1985	3.578
1986	5.654
1987	2.762
1988	2.909
1989	-1.424
1990	-3.132
1991	9.568
1992	13.827
1993	13.334
1994	10.492
1995	-3.446
1996	6.599
1997	-6.343
1998	4.682
1999	1.856
2000	-2.494
2001	-0.123
2002	-0.159
2003	9.046
2004	0.578
2005	4.252
2006	2.537
2007	7.815
2008	-0.296
2009	6.800
2010	10.128
2011	1.108
2012	4.657
2013	3.825
2014	13.544
2015	6.576
2016	5.492
2017	3.535
2018	-0.279
2019	4.480
2020	-3.167
2021	-0.780
2022	5.165
2023	2.681
2024	4.520
2025	3.698
2026	3.450
2027	3.065
2028	3.107
2029	3.113