The 10x there compares local currency to USD. Given the NOK to USD exchange rate, a 10x PPP difference between NOK and USD means Norway and the US are near pari

The 10x there compares local currency to USD. Given the NOK to USD exchange rate, a 10x PPP difference between NOK and USD means Norway and the US are near parity in terms of purchasing power in USD. Actually, the salaries are now much closer than I thought, so depending on exactly which measures you use I might well have been wrong that US salaries are (still) much higher than Norwegian ones. The gap used to be fairly huge.