Year	Percent change (Units)
1980	274.878
1981	-37.117
1982	-7.190
1983	3.392
1984	54.387
1985	-32.926
1986	6.193
1987	-14.257
1988	-19.840
1989	-2.562
1990	-14.627
1991	14.205
1992	-3.277
1993	-1.414
1994	-2.941
1995	6.611
1996	-32.467
1997	47.253
1998	-7.828
1999	6.528
2000	-31.287
2001	31.447
2002	27.844
2003	-10.120
2004	-30.194
2005	22.116
2006	-27.691
2007	73.428
2008	-11.170
2009	-6.360
2010	-2.590
2011	32.198
2012	2.963
2013	-12.950
2014	2.975
2015	7.433
2016	26.227
2017	-15.023
2018	-37.373
2019	75.556
2020	-37.502
2021	-53.722
2022	87.544
2023	1.566
2024	13.116
2025	9.356
2026	6.234
2027	5.080
2028	3.009
2029	8.305