obs	PB	PC	Y	YD
1960	20.4	12.2	23.52	20.22
1961	20.2	10.1	25.95	20.78
1962	21.3	10.2	25.94	21.71
1963	19.9	10	27.22	22.46
1964	18	9.2	27.82	24.1
1965	19.9	8.9	29.77	25.63
1966	22.2	9.7	32.08	27.34
1967	22.3	7.9	32.62	28.95
1968	23.4	8.2	32.88	31.14
1969	26.2	9.7	34.9	33.24
1970	27.1	9.1	36.88	35.87
1971	29	7.7	36.74	38.6
1972	33.5	9	38.49	41.4
1973	42.8	15.1	37.01	46.16
1974	35.6	9.7	36.93	50.1
1975	32.3	9.9	36.7	54.98
1976	33.7	12.9	39.84	59.72
1977	34.5	12	40.71	65.17
1978	48.5	12.4	43.1	72.24
1979	66.1	13.9	46.64	79.67
1980	62.4	11	46.91	88.22
1981	58.6	11.1	48.45	97.65
1982	56.7	10.3	49.52	104.26
1983	55.5	12.7	50.83	111.31
1984	57.3	15.9	52.83	123.19
1985	53.7	14.8	54.81	130.37
1986	52.6	12.5	56.47	136.49
1987	61.1	11	60.27	142.41
1988	66.6	9.2	62.28	152.97
1989	69.5	14.9	66.17	162.57
1990	74.6	9.3	69.08	171.31
1991	72.7	7.1	72.12	176.09
1992	71.3	8.6	75.38	184.94
1993	72.6	10	77.14	188.72
1994	66.7	7.4	78.61	195.55
1995	61.8	6.5	78.23	202.87
1996	58.7	6.6	81.42	210.91
1997	63.1	7.7	83.67	219.4
1998	59.6	8.1	83.89	231.61
1999	63.4	7.1	88.87	239.68