Gas

1990

1991

1992

1993

1994

1995

1996

1997

1998

P1999

Carbon Dioxide

4,951.9

4,907.6

5,005.3

5,121.6

5,215.7

5,260.6

5,441.6

5,519.0

5,527.1

5,598.2

Methane

31.7

31.9

32.0

31.1

31.2

31.2

30.2

30.1

29.3

28.8

Nitrous Oxide

1.2

1.2

1.2

1.2

1.3

1.3

1.2

1.2

1.2

1.2

HFCs, PFCs, and SF₆

*

*

*

*

*

*

*

*

*

*

*Less than 0.05 million metric tons of gas.
P = preliminary data.
Note: Data in this table are revised from the data contained in the previous EIA report, Emissions of Greenhouse Gases in the United States 1998, DOE/EIA-0573(98) (Washington, DC, October 1999).
Source: Estimates presented in this report.