Does the website reference net or gross monthly income?

Edit:

So the numbers are not a direct exchange rate to USD.

Q: How were dollar values assigned to households? A: The households’ door numbers represent the consumption values (US dollars) that each adult in the household has per month. This figure comes from a combination of the household’s self-reported consumption and income levels. We then checked the official cost of living data in each country to adjust the values for purchasing power parity (PPP) and converted the value into US dollars. Read more about how we assigned the Dollar Street values here.