The following data indicate the median price of unleaded gasoline during the last 10 years for California

Question:

The following data indicate the median price of unleaded gasoline during the last 10 years for California residents:
Period Price ($)
1999......................... $1.20
2009.......................... $3.62
Assuming that the base period (price index = 100) is 1999. Compute the average price index for the unleaded gasoline price for the year 2009.