Year	Percent change (Units)
1980	188.816
1981	33.700
1982	70.381
1983	62.511
1984	27.175
1985	114.698
1986	35.002
1987	6.112
1988	14.800
1989	59.700
1990	-26.317
1991	13.439
1992	9.847
1993	5.650
1994	7.670
1995	19.075
1996	19.147
1997	19.544
1998	90.141
1999	128.409
2000	8.369
2001	7.809
2002	10.633
2003	15.489
2004	10.467
2005	7.167
2006	6.546
2007	4.662
2008	7.629
2009	0.141
2010	5.983
2011	7.569
2012	4.255
2013	6.371
2014	4.129
2015	1.277
2016	1.597
2017	0.825
2018	2.040
2019	3.323
2020	5.104
2021	3.754
2022	22.959
2023	31.230
2024	21.500
2025	14.750
2026	7.000
2027	3.000
2028	3.000
2029	3.000