Table 1.

Means (standard deviation) and proportions (%) of the sample characteristics and the sleep variables from all available days of actigraphy recording.

Demographic Variables
Age (years), Mean (SD)	42.9 (3.7)
Black (%)	44%
Female (%)	57%
Education (%)
< High School	5%
High School	15%
Some College	28%
College Degree	25%
Postgraduate	27%
Income (%)
<$35,000/year	34%
≥$35,000/year	66%
Employment Status (%)
Full-time	74%
Part-time	11%
Not employed	15%
Sleep Variables Mean (SD)	Year 1	Year 2	Overall
Average time in bed (hours)	7.5	7.5	7.5
	(1.2)	(1.3)	(1.1)
Average sleep duration (hours)	6.1	6.1	6.1
	(1.2)	(1.2)	(1.1)
Average sleep latency (minutes)	22.3	21.7	22.6
	(30.2)	(33.6)	(30.0)
Average sleep efficiency (%)	81.0	81.2	80.8
	(10.8)	(10.6)	(10.5)