Year	Percent change (Units)
1980	21.664
1981	7.523
1982	7.643
1983	5.629
1984	20.152
1985	45.336
1986	7.639
1987	13.551
1988	43.864
1989	40.658
1990	50.463
1991	47.079
1992	4.259
1993	5.250
1994	8.261
1995	12.536
1996	5.399
1997	8.297
1998	4.832
1999	6.471
2000	7.723
2001	8.884
2002	5.223
2003	27.450
2004	51.461
2005	4.190
2006	7.573
2007	6.144
2008	10.644
2009	1.442
2010	6.330
2011	8.459
2012	3.694
2013	4.831
2014	2.999
2015	0.837
2016	1.614
2017	3.280
2018	3.564
2019	1.811
2020	3.781
2021	8.243
2022	8.812
2023	4.786
2024	4.229
2025	3.973
2026	3.973
2027	3.973
2028	3.973
2029	3.973