"Year"	"Extent"	"Area"	"t"
1979	7.22	4.54	1
1980	7.86	4.83	2
1981	7.25	4.38	3
1982	7.45	4.38	4
1983	7.54	4.64	5
1984	7.11	4.04	6
1985	6.93	4.18	7
1986	7.55	4.67	8
1987	7.51	5.61	9
1988	7.53	5.32	10
1989	7.08	4.83	11
1990	6.27	4.51	12
1991	6.59	4.47	13
1992	7.59	5.38	14
1993	6.54	4.53	15
1994	7.24	5.09	16
1995	6.18	4.39	17
1996	7.91	5.6	18
1997	6.78	4.85	19
1998	6.62	4.26	20
1999	6.29	4.24	21
2000	6.36	4.32	22
2001	6.78	4.56	23
2002	5.98	3.99	24
2003	6.18	4.02	25
2004	6.08	4.36	26
2005	5.59	4.04	27
2006	5.95	3.98	28
2007	4.32	2.79	29
2008	4.73	3.22	30
2009	5.39	3.72	31
2010	4.93	3.29	32
2011	4.63	3.18	33
2012	3.63	2.37	34
2013	5.35	3.75	35
2014	5.29	3.7	36
2015	4.68	3.37	37
