So your point would be that countries like Greece should pay the same amount as the United States even though their Gross National Incomes aren't even close to being the same?
Today, the volume of the US defence expenditure effectively represents 73 per cent of the defence spending of the Alliance as a whole. This does not mean that the United States covers 73 per cent of the costs involved in the operational running of NATO as an organisation, including its headquarters in Brussels and its subordinate military commands, but it does mean that there is an over-reliance by the Alliance as a whole on the United States for the provision of essential capabilities, including for instance, in regard to intelligence, surveillance and reconnaissance; air-to-air refuelling; ballistic missile defence; and airborne electronic warfare.
How about the rest of NATO just try a little bit?