Since 1993, ERS has calculated these prices based on 5-year lagged averages of actual market prices (e.g., an average of 2008-12 market prices is used to calculate 2014 normalized prices). State-level normalized prices for 2014 were calculated by multiplying the national-level normalized prices by the average ratios of the State-level market prices to the national market prices for 2010-12.
All data are gathered from the annual Agricultural Prices report from USDA's National Agricultural Statistical Service.
The next update of the normalized prices series is expected to contain estimates for 2015. These estimates should appear at the end of September 2015 as an update to this data product.