Oregon’s Jackson County has tested more people per capita for coronavirus than every state except New York, Washington and Louisiana — three viral hotspots with thousands of patients, according to an analysis of state and national data .

The county, which ranks sixth in population in Oregon with about 217,500 people, is testing at more than twice the rate of the state overall, the analysis found.

Jackson County public health officials and representatives of the region’s medical systems, which carry out testing, said they don’t really know why the county’s testing rates are so high. They suggested it was their preparation, the county’s relatively small size and possibly the quick response. All said they’re following the state’s narrow testing guidelines for the sickest people.

As of Friday, the Southern Oregon county tested 2,028 people, a rate of 9.375 per thousand. The state’s testing rate is 3.8. New York, Washington and Louisiana have testing rates of 9.8 per thousand or above, according to the COVID Tracking Project, which tracks testing rates nationally.

That’s critical because the true number of infections has been dramatically undercounted as many people have struggled to qualify for testing unless they have severe symptoms.