Table 1.

Distributions of self-reported insomnia-related symptoms (N = 12,502)

Question and response alternatives*	Men (%)	Women (%)
INSOMNIA-SYMPTOM
How often do you suffer from insomnia?
never or less than once a month	50.8	51.4
less than one night per week	30.2	28.9
1–2 nights per week	12.2	12.3
3 nights or more per week	6.8	7.4
DIFFICULTY IN INITIATING SLEEP
Do you have difficulties in falling asleep in the evening?
never or less than once a month	55.4	56.0
less than once a week	25.8	25.0
1–2 evenings per week	11.8	11.1
3 evenings or more per week	7.1	7.9
SLEEP LATENCY
How fast do you usually fall asleep in the evening?
in less than 10 minutes	33.0	30.1
in 10–20 minutes	43.9	44.3
in 21–30 minutes	14.3	15.9
more than 30 minutes	8.8	9.7
NOCTURNAL AWAKENINGS
How often on average are you awaken during the night?
usually I do not wake during the night	30.5	25.8
at most during a couple nights a week	25.1	22.7
once a night	23.5	25.2
twice a night	13.6	17.1
3 times or more a night	7.3	9.3
EARLY MORNING AWAKENING
I sleep as well as before
when I wake up in the morning I am much more sleepy/tired than before	79.4	73.4
“I wake up 1–2 hours earlier than before and it is difficult to fall asleep again ”or	11.4	17.2
“I wake up early every morning, and I cannot sleep more than 5 hours”	9.2	9.4
NON-RESTORATIVE SLEEP (MORNING)
How often do you feel sleepy/tired when you wake up in the morning?
never or less than once a month	32.8	29.8
less than one morning per week	33.1	29.2
1–2 mornings per week	20.2	21.5
3–5 mornings per week	6.7	7.7
every or almost every morning	7.2	11.8
NON-RESTORATIVE SLEEP (DAY)
Are you sleepy/tired during the daytime?
never or less than once a month	33.0	28.9
less than one day per week	34.3	31.2
1–2 days per week	19.6	22.2
3–5 days per week	5.9	6.7
every or almost every day	7.1	11.1

^*Range of missing data on each question 0.3–1.7%