Year	Percent change (Units)
1980	40.979
1981	0.744
1982	9.786
1983	-1.229
1984	-5.491
1985	21.665
1986	-6.475
1987	282.627
1988	-2.794
1989	7.157
1990	3.618
1991	-16.319
1992	-0.244
1993	-4.040
1994	33.454
1995	6.825
1996	-19.603
1997	26.373
1998	6.755
1999	-7.397
2000	0.272
2001	-5.708
2002	-15.579
2003	-23.178
2004	7.789
2005	0.647
2006	-0.210
2007	8.734
2008	-1.534
2009	9.684
2010	13.476
2011	-14.805
2012	8.766
2013	-29.195
2014	84.000
2015	23.854
2016	12.075
2017	-2.336
2018	0.512
2019	7.845
2020	4.492
2021	-10.452
2022	-4.207
2023	5.033
2024	5.933
2025	9.589
2026	4.123
2027	7.941
2028	5.462
2029	5.505