Usually used to characterize a city or region in terms of its propensity for conservative, traditional, and Christian values, versus its tendency toward progressive, New Age, and secular thinking. Can also be applied to an individual person.
For example, San Francisco has about a 10-90 NRA-NPR ratio, whereas some of the more rural Southeastern states would be the reverse. A diverse hybrid city like New York is probably 50-50.
Dude, the NRA-NPR ratio is like 90-10.