Year	Percent change (Units)
1980	1.128
1981	40.454
1982	12.544
1983	-3.103
1984	-3.414
1985	-17.393
1986	25.504
1987	2.625
1988	-0.371
1989	15.791
1990	-32.590
1991	-0.094
1992	-40.104
1993	42.705
1994	-37.899
1995	4.629
1996	1.312
1997	26.305
1998	12.019
1999	14.280
2000	9.260
2001	5.105
2002	5.822
2003	-7.415
2004	13.961
2005	58.278
2006	-14.853
2007	4.163
2008	16.090
2009	-6.838
2010	24.233
2011	23.594
2012	-14.858
2013	-12.467
2014	-13.871
2015	4.901
2016	-4.029
2017	-4.421
2018	-1.440
2019	2.171
2020	-2.306
2021	-13.933
2022	43.550
2023	-0.464
2024	-17.133
2025	8.011
2026	-0.243
2027	-0.937
2028	5.077
2029	4.004