I'm not quite sure what official inflation index measures but you can get rough estimate of how much value dollar lost if you compare prices of bitcoin in dolla

I'm not quite sure what official inflation index measures but you can get rough estimate of how much value dollar lost if you compare prices of bitcoin in dollars and euro at the beginning and the end of the year. More concretely, if you converted 1btc to euro or dollar at the beginning of the year and back to btc at the end, how much fewer btc you'd end up with if you went through dollar as oppossed to euro.