How many hours did people sleep in 1900?

In 1900, people generally slept for much longer periods than modern-day human beings. People were often documented to have "first sleep" and "second sleep", waking and then falling asleep once more in a single eight-hour block of time. The average amount of sleep was estimated to be about 9 hours each night. As people moved from preindustrial, rural-based, pre-electricity living situations, to more urban and electrified routines their sleep began to get disturbed in many ways which has affected people's average amount of sleep since 1900.