Average Annual Price of Gasoline from 1990 to 2010 Adjusted for Inflation

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Statistics Project
Average Annual Price of Gasoline from 1990 to 2010 Adjusted For Inflation

Purpose: To analyze the price fluctuations of gasoline over a period of time between 1990 and 2010 using the annual average across all regions and gasoline grades and adjusted to today’s dollar.

Procedure: Historic gasoline prices are maintained by the Department of Energy on a weekly basis dating back between 16 and 21 years depending on the grade of gasoline and region of the United States where the price data was collected. There are 1,043 weekly data points between August 20, 1990 and September 27, 2010. This large number of data points makes it difficult to display the information usefully so I averaged the price of gasoline into yearly points reducing the number to 21 (Table A, provided for comparison of the raw unadjusted data only). I adjusted the data points for inflation to match the value of a U.S. Dollar in 2010 (Table B).

Data Collection: The Department of Energy publicizes the gasoline price data on their website at http://www.eia.doe.gov/petroleum/data_publications/wrgp/mogas_history.html. On the bottom of the web page is a link to an excel spreadsheet with a file name of pswrgvall.xls. The worksheet used was number 3 titled Data 3: Regular All Areas All Formulations. The Bureau of Labor Statistics maintains an inflation calculator that adjusts a given price to the selected year using the Consumer Price Index. For expediency After averaging the gasoline price data for the year I input it into the calculator to adjust for inflation. The online calculator can be found at http://www.bls.gov/data/inflation_calculator.htm.

Raw Data: Yearly Average Raw Data: Yearly Average Price Price of Gasoline For All of Gasoline For All Grades and All Grades and All Regions. Regions Adjusted for Inflation. Year| Price|

1990| $2.17|
1991| $1.76|
1992| $1.70|
1993| $1.62|
1994| $1.58|
1995| $1.59|
1996| $1.67|
1997| $1.63|
1998| $1.38|
1999| $1.49|
2000| $1.88|
2001| $1.75|
2002| $1.63|
2003| $1.85|
2004| $2.14|
2005| $2.54|
2006| $2.78|
2007| $2.95|
2008| $3.30|
2009| $2.39|
2010| $2.75|

Year| Price|
1990| $1.30|
1991| $1.10|
1992| $1.09|
1993| $1.07|
1994| $1.07|
1995| $1.11|
1996| $1.20|
1997| $1.20|
1998| $1.03|
1999| $1.14|
2000| $1.48|
2001| $1.42|
2002| $1.34|
2003| $1.56|
2004| $1.85|
2005| $2.27|
2006| $2.57|
2007| $2.80|
2008| $3.25|
2009| $2.35|
2010| $2.75|

Table A Table B

Price Data, in ascending order:
1.38| 1.49| 1.58| 1.59| 1.62| 1.63| 1.63| 1.67| 1.70| 1.75| 1.76| 1.85| 1.88| 2.14| 2.17| 2.39| 2.54| 2.75| 2.78| 2.95| 3.30| | | | | | | | | |

Adjusting for Inflation: (dollar amout)CPI Indexpresent year CPI Indexpast year=x x=adjusted price

For example:
CPI 1990=128.7
CPI 2010=214.537
Dollar amount: $1.30 (the price of a gallon of gas in 1990)

1.30214.537128.7 =x

1.301.67=2.17

Frequency Distribution:

Yearly Average Price of Gasoline for All Grades and All Regions Adjusted for Inflation.| | | | | | | | | | |
Price(dollars)| Frequency| Percentage| | | | |
1.25 but less than 1.50| 2| 9%| | | | |
1.50 but less than 1.75| 7| 33%| | | | |
1.75 but less than 2.00| 4| 19%| | | | |
2.00 but less than 2.25| 2| 9%| | | | |
2.25 but less than 2.50| 1| 4%| | | | |
2.50 but less than 2.75 | 1| 4%| | | | |
2.75 but less than 3.00| 3| 14%| | | | |
3.00 but less than 3.25| 1| 4%| | | | |
3.25 but...
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