Year	Percent change (Units)
1980	50.005
1981	116.504
1982	22.485
1983	122.245
1984	40.030
1985	10.301
1986	24.539
1987	39.758
1988	31.369
1989	25.237
1990	37.241
1991	18.097
1992	10.049
1993	24.942
1994	24.874
1995	59.317
1996	44.487
1997	24.825
1998	19.208
1999	12.471
2000	25.113
2001	32.932
2002	14.846
2003	26.626
2004	12.666
2005	15.095
2006	11.683
2007	10.729
2008	16.505
2009	13.139
2010	6.698
2011	7.676
2012	7.072
2013	11.666
2014	15.486
2015	17.153
2016	17.455
2017	12.372
2018	9.837
2019	7.144
2020	9.885
2021	9.976
2022	31.713
2023	37.531
2024	22.271
2025	11.506
2026	8.000
2027	8.000
2028	8.000
2029	8.000