Year	Percent change (Units)
1981	1.070
1982	-3.049
1983	0.468
1984	7.318
1985	2.061
1986	8.163
1987	4.917
1988	6.508
1989	4.940
1990	3.781
1991	2.304
1992	4.564
1993	4.645
1994	4.186
1995	4.549
1996	2.314
1997	4.880
1998	6.518
1999	4.413
2000	3.272
2001	9.468
2002	2.170
2003	2.341
2004	1.987
2005	-1.987
2006	-1.410
2007	-1.162
2008	-1.844
2009	-1.952
2010	-0.413
2011	-0.359
2012	0.029
2013	-0.307
2014	-1.190
2015	-1.049
2016	-1.263
2017	-2.886
2018	-4.364
2019	1.679
2020	-4.186
2021	0.412
2022	3.207
2023	-0.700
2024	-0.200
2025	0.000
2026	0.300
2027	1.700
2028	0.800
2029	0.800