Year	Percent change (Units)
1980	14.151
1981	8.678
1982	7.119
1983	4.374
1984	3.688
1985	10.852
1986	18.664
1987	53.418
1988	7.340
1989	0.758
1990	21.766
1991	10.488
1992	21.311
1993	79.263
1994	142.841
1995	24.162
1996	2.840
1997	6.081
1998	11.248
1999	60.526
2000	29.557
2001	34.366
2002	15.516
2003	23.001
2004	9.126
2005	13.981
2006	11.281
2007	6.426
2008	14.667
2009	-0.300
2010	6.948
2011	17.684
2012	5.009
2013	1.916
2014	3.384
2015	6.896
2016	55.501
2017	22.024
2018	6.939
2019	4.392
2020	34.890
2021	59.120
2022	52.448
2023	51.582
2024	20.741
2025	14.814
2026	9.728
2027	7.572
2028	5.000
2029	5.000