>I'm not in the US, but our inflation data was just as wrong as I've heard the US data was. Official numbers were 10% but literally everything went up at least 20%. Everyone I spoke to had their cost of living increase by significantly more than the official inflation figures.

All the math that underpins the usual idiots screeching about "muh compounding gains/interest" applies to the divergence between real inflation and official inflation as well. You can hide a lot of divergence between the real value of the currency and the official value by "simply" having the official number be low by a couple percent over time.