Year	Percent change (Units)
1980	6.595
1981	47.849
1982	-21.612
1983	-14.352
1984	-1.564
1985	-31.403
1986	-30.467
1987	0.800
1988	0.942
1989	14.592
1990	9.300
1991	6.308
1992	-9.729
1993	20.991
1994	-22.317
1995	-15.252
1996	15.834
1997	9.281
1998	-27.837
1999	0.292
2000	-11.353
2001	20.534
2002	49.732
2003	18.987
2004	-10.507
2005	13.581
2006	0.429
2007	24.482
2008	7.583
2009	21.261
2010	7.180
2011	-59.777
2012	137.573
2013	31.484
2014	-8.603
2015	-34.503
2016	-44.645
2017	14.934
2018	22.382
2019	34.765
2020	-46.736
2021	59.721
2022	1.146
2023	0.004
2024	-0.113
2025	0.489
2026	0.500
2027	-0.721
2028	-1.009
2029	-1.034