Year	Percent change (Units)
1980	3.229
1981	54.020
1982	-1.528
1983	-16.190
1984	66.500
1985	18.300
1986	-4.600
1987	-23.033
1988	14.359
1989	-10.017
1990	15.167
1991	4.244
1992	13.502
1993	-6.526
1994	-6.925
1995	3.749
1996	-4.621
1997	4.414
1998	-10.880
1999	-2.431
2000	-9.045
2001	7.150
2002	10.227
2003	10.420
2004	5.133
2005	6.472
2006	7.114
2007	0.734
2008	15.969
2009	10.342
2010	2.830
2011	0.244
2012	3.683
2013	6.891
2014	-3.881
2015	-4.344
2016	9.097
2017	3.924
2018	8.678
2019	0.087
2020	1.739
2021	8.509
2022	-1.398
2023	26.095
2024	-1.010
2025	1.779
2026	10.978
2027	6.265
2028	5.776
2029	5.245