Quarter	Millions of US Dollars
1972-04-01	32
1972-07-01	31
1972-10-01	51
1973-01-01	55
1973-04-01	61
1973-07-01	61
1973-10-01	57
1974-01-01	59
1974-04-01	59
1974-07-01	58
1974-10-01	61
1975-01-01	63
1975-04-01	62
1975-07-01	58
1975-10-01	58
1976-01-01	59
1976-04-01	59
1976-07-01	61
1976-10-01	97
1977-01-01	159
1977-04-01	163
1977-07-01	166
1977-10-01	244
1978-01-01	258
1978-04-01	266
1978-07-01	288
1978-10-01	290
1979-01-01	276
1979-04-01	273
1979-07-01	279
1979-10-01	271
1980-01-01	250
1980-04-01	279
1980-07-01	279
1980-10-01	274
1981-01-01	261
1981-04-01	239
1981-07-01	239
1981-10-01	250
1982-01-01	230
1982-04-01	182
1982-07-01	176
1982-10-01	194
1983-01-01	149
1983-04-01	148
1983-07-01	150
1983-10-01	151
1984-01-01	155
1984-04-01	147
1984-07-01	142
1984-10-01	139
1985-01-01	139
1985-04-01	140
1985-07-01	158
1985-10-01	135
1986-01-01	145
1986-04-01	159
1986-07-01	169
1986-10-01	89
1987-01-01	97
1987-04-01	96
1987-07-01	96
1987-10-01	113
1988-01-01	110
1988-04-01	101
1988-07-01	99
1988-10-01	27