It's time again for my weekly gasoline update based on data from the Energy Information Administration (EIA). Rounded to the penny, Regular dropped a penny and Premium was unchanged -- the reverse of last week's pattern.

According to GasBuddy.com, California has the highest average price at $3.20. South Carolina has the cheapest Regular at $2.09.

How far are we from the interim high prices of 2011 and the all-time highs of 2008? Here's a visual answer.

The next chart is a monthly chart overlay of West Texas Light Crude, Brent Crude and unleaded gasoline end-of-day spot prices (GASO).

WTIC closed today at $48.72 a barrel, off the interim low nine sessions ago.

The volatility in crude oil and gasoline prices has been clearly reflected in recent years in both the Consumer Price Index (CPI) and Personal Consumption Expenditures (PCE). For additional perspective on how energy prices are factored into the CPI, see What Inflation Means to You: Inside the Consumer Price Index.

The chart below offers a comparison of the broader aggregate category of energy inflation since 2000, based on categories within Consumer Price Index (commentary here).