Quarter	Millions of US Dollars
1972-04-01	11
1972-07-01	11
1972-10-01	11
1973-01-01	12
1973-04-01	14
1973-07-01	14
1973-10-01	12
1974-01-01	13
1974-04-01	13
1974-07-01	13
1974-10-01	14
1975-01-01	14
1975-04-01	14
1975-07-01	13
1975-10-01	13
1976-01-01	13
1976-04-01	13
1976-07-01	13
1976-10-01	14
1977-01-01	14
1977-04-01	14
1977-07-01	14
1977-10-01	15
1978-01-01	16
1978-04-01	15
1978-07-01	16
1978-10-01	17
1979-01-01	17
1979-04-01	17
1979-07-01	18
1979-10-01	18
1980-01-01	16
1980-04-01	18
1980-07-01	17
1980-10-01	16
1981-01-01	15
1981-04-01	13
1981-07-01	13
1981-10-01	13
1982-01-01	11
1982-04-01	11
1982-07-01	10
1982-10-01	11
1983-01-01	10
1983-04-01	10
1983-07-01	9
1983-10-01	9
1984-01-01	9
1984-04-01	9
1984-07-01	8
1984-10-01	8
1985-01-01	8
1985-04-01	8
1985-07-01	9
1985-10-01	1
1986-01-01	1
1986-04-01	1
1986-07-01	1
1986-10-01	1
1987-01-01	1
2018-01-01	3
2018-04-01	3