Table 1.

Descriptive Statistics of the Study Population

	Group	N	%
Total ICU stays		730,222	100
Age group	0–20	15,728	3.2
	21–40	67,247	13.2
	41–60	202,738	33.8
	61–80	320,289	38.3
	81+	124,220	11.4
Gender	Female	341,590	63.1
	Male	388,632	36.9
Race	Caucasian	483,543	59.6
	African American	100,296	20.4
	Other	146,383	20.1
Census region	West	80,515	11.1
	Midwest	260,302	35.6
	South	208,026	28.5
	Northeast	181,379	24.8
Year	2006	35,976	4.9
	2007	128,229	17.6
	2008	63,513	8.7
	2009	25,174	3.4
	2010	53,881	7.4
	2011	148,728	20.4
	2012	83,394	11.4
	2013	61,437	8.4
	2014	20,198	2.8
	2015	109,692	15.0