UNDATED -- The U.S. national average price of gas has fallen under the $4 mark to $3.99 a gallon.

This is the first time since March that the national average has dropped below the $4 mark.

Gas prices have declined by over $1 per gallon since peaking at $5.03 on June 14th.

Gas prices in Minnesota fell to an average of $3.97 per gallon as of Monday morning.

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LOOK: See how much gasoline cost the year you started driving

To find out more about how has the price of gas changed throughout the years, Stacker ran the numbers on the cost of a gallon of gasoline for each of the last 84 years. Using data from the Bureau of Labor Statistics (released in April 2020), we analyzed the average price for a gallon of unleaded regular gasoline from 1976 to 2020 along with the Consumer Price Index (CPI) for unleaded regular gasoline from 1937 to 1976, including the absolute and inflation-adjusted prices for each year.

Read on to explore the cost of gas over time and rediscover just how much a gallon was when you first started driving.

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