Producer price indexes track the changes in the payments producers receive for their output.
The UK Producer Price Index is produced by the Office of National Statistics. This index is based around prices in 2010 being set at "100" - if the current value is higher than 100, prices have gone up, if it is lower, prices have gone down. Monetary values are not available - the index can only be used to track trends in sectors.
The USA Producer Price Index is more detailed (and easier to use) than the UK version, but is based on output values from the United States.
ALPs - contact the library at your institution