Some things that define Arizona can be measured, like the depth of Grand Canyon and the miles between gas stations on empty desert roads.

Measuring the state’s population, though, is a lot harder.

Arizona is lagging behind the rest of the country in responding to the census, as efforts to tally residents in some of the hardest to reach corners of the state have only recently resumed after a hiatus due to public health concerns.

About 58% of Arizona households had responded to the census as of July 2, compared to nearly 62% of the country, and that rate is even higher in some areas, reaching 71% in Minnesota.

Arizona's rate of response to the census this year is not too far behind its rate in 2010, but the share of people who have participated in some of the areas that are often tougher to count remains low. The response rate in Apache County was only about 11% as of this week, for example — one of the lowest rates in the country.