Year	Percent change (Units)
1980	-15.786
1981	6.612
1982	18.081
1983	-4.967
1984	-5.674
1985	9.992
1986	-24.664
1987	20.184
1988	-12.613
1989	36.159
1990	-7.374
1991	0.752
1992	-14.105
1993	19.064
1994	11.664
1995	0.279
1996	-8.789
1997	29.765
1998	-4.711
1999	3.541
2000	23.166
2001	-3.911
2002	8.395
2003	-33.507
2004	-2.069
2005	-7.408
2006	17.893
2007	4.790
2008	-15.415
2009	-24.393
2010	11.952
2011	7.691
2012	9.409
2013	-50.015
2014	-22.420
2015	-15.428
2016	52.347
2017	42.477
2018	10.313
2019	-6.685
2020	9.353
2021	-5.295
2022	2.596
2023	8.976
2024	5.245
2025	8.959
2026	5.423
2027	8.879
2028	5.200
2029	5.218