Table 2.4.—Value of the Resource, Additions, and Depletion of Gas, Present Discounted Value Method Using 10% Discount Rate

[Billions of current dollars]

Year	Opening stock	Additions	Depletion	Revaluation adjustment	Closing stock (1+2-3+4)
	(1)	(2)	(3)	(4)	(5)
1947			0.1		3.9
1948	3.9	.3	.1	.5	4.5
1949	4.5	.2	.1	.1	4.7
1950	4.7	.2	.1	0	4.8
1951	4.8	.3	.1	.1	5.1
1952	5.1	.3	.2	.2	5.4
1953	5.4	.5	.2	1.0	6.7
1954	6.7	.3	.2	1.4	8.1
1955	8.1	.7	.3	1.4	9.9
1956	9.9	.9	.4	.4	10.8
1957	10.8	.7	.4	.4	11.5
1958	11.5	.7	.4	1.2	13.0
1959	13.0	.8	.5	.1	13.5
1960	13.5	.6	.5	1.5	15.1
1961	15.1	.8	.6	1.2	16.4
1962	16.4	1.0	.7	1.0	17.7
1963	17.7	1.0	.8	.8	18.7
1964	18.7	1.1	.8	0	19.0
1965	19.0	1.1	.8	-.3	19.0
1966	19.0	1.0	.9	-.5	18.7
1967	18.7	1.1	.9	.5	19.3
1968	19.3	.7	1.0	-.2	18.8
1969	18.8	.4	1.0	-.4	17.8
1970	17.8	1.9	1.1	.9	19.5
1971	19.5	.5	1.2	-.4	18.5
1972	18.5	.5	1.1	-.3	17.5
1973	17.5	.3	1.1	1.8	18.5
1974	18.5	.5	1.3	4.7	22.5
1975	22.5	1.0	1.7	9.6	31.4
1976	31.4	1.0	2.6	14.0	43.9
1977	43.9	2.6	3.7	12.7	55.5
1978	55.5	2.7	4.5	11.8	65.5
1979	65.5	4.6	5.8	18.9	83.2
1980	83.2	8.2	6.3	11.6	96.7
1981	96.7	7.2	6.0	-5.2	92.7
1982	92.7	9.9	9.6	53.1	146.1
1983	146.1	13.3	13.8	75.6	221.2
1984	221.2	15.3	17.6	15.4	234.2
1985	234.2	12.3	16.0	-28.2	202.2
1986	202.2	12.8	14.2	-22.2	178.7
1987	178.7	8.9	12.1	-35.4	140.1
1988	140.1	-1.0	8.8	-36.7	93.6
1989	93.6	7.4	7.8	-2.9	90.3
1990	90.3	9.6	8.5	4.1	95.5
1991	95.5	7.3	8.3	-1.8	92.6