USA

American questions cover a country that measures itself unusually thoroughly, which means the figures here are mostly administrative records rather than estimates. Census counts, federal registries and agency reports give a level of precision that most countries cannot match, and the questions lean on that.

The useful anchors are the population, around three hundred and forty million, and the median household income. Between those two you can derive a surprising share of the answers in this category — anything measured per person, per household or per state is a division away, and rates per thousand people transfer cleanly from other countries you know.

The structural theme running through many of these is decentralisation. Policing, education, taxation and licensing are set at state or local level rather than nationally, so a single national figure frequently describes an average across thousands of independent authorities. Knowing that explains why so many of these numbers resist the reforms proposed for them.