How To Get An Overview Of Free Rooms

have six different locations in a city in which I have 6 beds for people with psyhiatric problems to sleep in.

The managers of the different location send me whenever somebody new comes or somebody leaves the following information:

Name of client
Start date of stay (when new clients arrive)
End date of stay (when client leaves)

I have to keep all record of clients that have used our locations, so the list gets very long during the year and it is then very hard to see which beds are still available.

What I would like to see in a separate sheet is which location still has how many beds available. I then mail this overview weekly to organizations that assign people to my locations.