Dear experts,

I have a dataset including monthly observations from June 2017 - June 2019, where I would like to calculate the 12-month relative change in price over a year for a specific product (i.e. pit=(pit/pit-12)). Whit the first possible number to get will then be June 2018.

Variable y_m is year and month such as 1804 corresponds to April 2018.

Any good advice on how to do this in STATA?

This is how the data looks like:

Array


Thank you,
Sofie