TABLE 1. Trends in suicide rates by large county level of urbanization* — United States, 1999–2015.

County urbanization level	No. of counties	No. of suicides	Overall annual suicide rate increase†	p-value	Joinpoint year
Large central metro	63	150,636	0.09	<0.01	—
Large fringe metro	352	133,479	0.20	<0.01	—

* Counties or county-equivalents; a small number of counties were combined into multicounty groupings. The six classification levels for counties were 1) large central metro: part of a metropolitan statistical area with ≥1 million population and covers a principal city; 2) large fringe metro: part of a metropolitan statistical area with ≥1 million population but does not cover a principal city; 3) medium metro: part of a metropolitan statistical area with ≥250,000 but <1 million population; 4) small metro: part of a metropolitan statistical area with <250,000 population; 5) micropolitan (non-metro): part of a micropolitan statistical area (has an urban cluster of ≥10,000 but <50,000 population); and 6) non-core (non-metro): not part of a metropolitan or micropolitan statistical area.

^† Per 100,000 residents aged ≥10 years, age-adjusted to the year 2000 U.S. standard.