In 1985 the minimum wage was about $3.35 per hour. Multiply that by an average days work of 7 hours, minus the taxes. And one ends up at around $19 cash for the day. Average price of gas in 1985 was $0.90 per gallon and average car is 10 gallon tank. Or $9.00 to fill up. Meaning to fill up ones car in 1985 it took 47% of 1 days wage.
Skip forward to today. Minimum wage is about $8.50 per hour. Multiplied by 7 hours work, minus taxes, and one receives about $48.50 cash for the day. Gas prices today are about $3.75 and still a 10 gallon tank or $37.50 for a fill up. Then it was 47% of 1 days wage to fill your tank, today that has jumped to 77% of a days wage.
The dollar amounts change over time to hide the fact that one is actually making less and less. Even though many assume they are making more because their wages went up. A person was richer in 1985 than they are in 2013.