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Note: These data are available in spreadsheet format by clicking the ''Download Series History'' link on the previous page (with drop-down menu bar at top).
View History:
Monthly
Annual
Rocky Mountain (PADD 4) Isobutane-Isobutylene Field Production (Thousand Barrels per Day)
Year
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
1981
0
0
0
0
0
0
0
0
0
0
0
0
1982
0
0
0
0
0
0
0
0
0
0
0
0
1983
0
0
0
0
0
0
0
0
0
0
0
0
1984
4
4
4
4
4
4
5
4
4
5
5
5
1985
5
5
5
5
5
4
5
5
6
5
5
5
1986
5
5
5
5
5
5
5
5
5
5
5
5
1987
5
6
6
6
6
6
5
6
6
6
6
7
1988
7
8
8
8
8
8
8
7
7
8
8
8
1989
7
8
8
8
8
6
7
7
8
8
8
8
1990
8
8
8
8
8
8
7
7
7
7
8
7
1991
8
9
8
9
10
10
11
10
11
10
9
9
1992
10
10
10
11
11
11
11
10
11
11
13
10
1993
9
10
11
11
10
10
10
10
10
11
10
10
1994
8
9
9
10
10
10
10
10
11
10
10
11
1995
10
10
10
10
11
11
11
11
10
10
10
11
1996
10
10
10
10
10
10
10
10
9
9
9
9
1997
9
9
10
10
10
10
10
9
11
10
9
10
1998
9
10
10
10
10
11
11
10
10
10
10
9
1999
10
10
10
10
10
12
11
11
11
11
12
12
2000
12
11
12
12
12
11
11
12
12
12
12
11
2001
11
11
11
12
12
12
11
11
11
10
11
10
2002
10
12
11
11
11
11
10
11
11
12
11
11
2003
10
11
11
10
10
11
10
11
10
11
10
10
2004
10
11
11
11
11
11
11
11
11
11
10
10
2005
9
10
10
10
10
10
10
10
10
10
10
9
2006
9
9
9
9
9
9
9
9
9
8
9
8
2007
9
9
9
8
8
8
8
9
10
9
10
10
2008
10
10
10
11
Updated on 6/26/2008
Source: U.S. Energy Information Administration
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