YEAR	JAN	FEB	MAR	APR	MAY	JUN	JUL	AUG	SEP	OCT	NOV	DEC
1974	NA	NA	NA	NA	NA	61	46.2	66.9	68.5	68.9	63.5	39
1975	32	52	54.5	48.7	64.1	59.6	64.7	72.8	74	73.3	67.5	67
1976	51.5	53.9	41.9	47.6	48.8	38.1	37.6	40.9	48.6	43.5	51.3	24.5
1977	24.4	44.4	19.4	36.6	48.9	50.1	42.8	50	53.7	48.5	36.5	8
1978	20.3	20.7	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
1979	23.4	25.4	32.7	42.5	43.3	48.9	54	54.1	52.5	40.8	40.4	29
1980	43.8	41.8	20	37.6	40.1	33.2	41.5	36.9	54.5	47.2	42.1	42.2
1981	40.8	24.1	22.2	23.3	50.9	49.4	47.8	64.8	53.6	54.8	51.9	34.7
1982	49.5	36.9	28.4	37.1	49.7	40.1	27.2	24.9	32.6	24	16.2	22.9
1983	11.3	24.7	38	42.7	29.7	28.9	29.9	49	52.1	57.3	51	53.9
1984	61.9	64.8	55.7	54.6	53.4	50.7	47	53.7	57.8	54.9	44.6	39.1
1985	37.3	54.3	26	49.8	60.3	51.4	51.4	57.4	53.6	55	45.6	37.9
1986	37.7	49.7	54.8	43.9	48.3	40.3	43	53.5	37.7	40.3	24.8	-0.4
1987	-1.2	-1	16.5	17.6	13.3	24.5	12.5	25.8	43.8	33.7	37.4	17.6
1988	21	23.6	44	40.9	51.4	57.3	59.8	67.9	70.4	65.2	65.8	61.5
1989	61.1	61.2	57.4	47.2	49.1	53.8	52	57.7	62.2	55.9	37.8	34.5
1990	19.8	19.8	14.7	25.8	42.3	45.5	43	39.9	43.3	50.3	40.7	29.7
1991	27.9	25.7	30.8	36.9	41.9	40.5	38.9	34.5	42.5	42.9	8.8	8.6
1992	0.6	14.8	5.4	11.8	14.6	28	39.1	46.8	53.1	44.2	30.8	13.3
1993	23.5	9.7	21.7	5.4	19.7	22.4	25.9	40.6	40.1	28.3	45.9	26.8
1994	33.5	44.7	41.3	32	40.5	45.4	41.5	41.2	37.5	43.3	25.7	-6.9
1995	8.5	25.2	36.7	40.3	46	50.6	52.1	61.9	59.5	66	60.7	52.8
1996	61.7	60.4	53.5	43.5	49.2	51.8	53.4	58.9	63.9	59.5	56.1	47.3
1997	41.9	42.5	21.6	19	16.3	29.7	22.8	24.8	32.8	12.2	38.8	14.4
1998	24	30.2	39.2	53.3	37.4	42.9	53.3	60.7	68.2	64.3	64	57.3
1999	62.5	54.5	59.8	53.3	53.8	52.1	49.6	61.5	69.4	65.9	59	65.3
2000	62	68.8	64.3	55.2	48.5	55.9	57.9	48.8	62.4	57.5	58.2	52.2
2001	58.7	44.7	49.5	37.6	39.8	44	45.9	44.6	58.3	50.3	41.2	8.7
2002	31.7	16	22.1	41.3	45	32	49.3	25.9	24.1	29.4	20	12.9
2003	-0.9	18.5	24.7	42.3	44.1	56.1	42.2	57.9	53.1	51.9	55.2	36
2004	21.3	41.7	29.2	24.1	46.6	26.9	48.3	44.6	48.8	47.3	36.1	35.7
2005	32.5	0.3	37.1	29.4	39.4	45.5	36.7	56	51.9	52	54.5	50.2
2006	47.9	40.8	53.5	41.9	53.3	37.4	46.6	42.9	46.5	35.7	36.8	25.4
2007	12.3	34.1	43.1	36.1	43.7	49.8	56.4	56.1	61.5	67.1	51.4	60.2
2008	44.1	67.9	65.4	55.7	57.2	47.9	53.8	57.2	54.5	63.1	56.2	62
2009	54.3	55.9	51.7	NA	NA	NA	NA	NA	NA	NA	NA	NA