Year	Percent change (Units)
1980	-17.413
1981	6.488
1982	-3.596
1983	-7.643
1984	31.382
1985	-17.431
1986	-38.691
1987	34.760
1988	7.995
1989	-11.331
1990	-16.368
1991	-2.119
1992	19.522
1993	0.450
1994	-0.600
1995	18.800
1996	2.508
1997	12.788
1998	-1.870
1999	-17.723
2000	-17.161
2001	1.215
2002	8.858
2003	6.462
2004	24.508
2005	9.086
2006	7.663
2007	19.623
2008	2.478
2009	-11.716
2010	11.039
2011	12.554
2012	2.038
2013	9.632
2014	3.121
2015	6.441
2016	8.612
2017	5.747
2018	1.741
2019	3.970
2020	-10.285
2021	7.928
2022	8.014
2023	3.342
2024	3.549
2025	3.671
2026	3.432
2027	3.123
2028	3.004
2029	2.926