Yakima, July 16- Average retail gasoline prices in Yakima have fallen 4.2 cents per gallon in the past week, averaging $3.55/g yesterday. This compares with the national average that has not moved  in the last week to $3.42/g, according to gasoline price website YakimaGasPrices.com.

Including the change in gas prices in Yakima during the past week, prices yesterday were 21.7 cents per gallon lower than the same day one year ago and are 47.8 cents per gallon lower than a month ago. The national average has decreased 11.0 cents per gallon during the last month and stands 24.7 cents per gallon lower than this day one year ago.