Not at all, they could simply report the real cost difference in the basket as well as the adjusted cost. Every year we don't see a matrix of GDP compared to bo

Not at all, they could simply report the real cost difference in the basket as well as the adjusted cost. Every year we don't see a matrix of GDP compared to both the real and nominal GDP of all previous years. We see those two numbers compared to last year and it's left to basic mathematics to do longer term comparisons. Part of the challenge is with how frequently they decide to change the basket of goods. If the basket was largely stable over time we would have a pretty good estimate simply by aggregating annual data, especially if they focus on staple consumables that don't change drastically over time.