force vs displacement hysteresis loops

Hi,

I am trying to analysis a series (1000) hysteresis loops created by loading and unloading (between 0 - 2kN) a sample. Ideally I would like to know what the area within each loop is as I am trying to calculate a damping ratio for each of the different samples I have tested. The trouble with the date is that the machine recorded 10 readings every second, and the frequency was set at 10Hz - so the data I have is didn't to interpret/ analysis. Data is in the link.

http://www.4shared.com/file/eHOrUfJO/Bolt_connection_-_1000cycles_-.html

I am quite new to MatLab and only know basic,

Any help would be hugely appreciated!!!!

Thanks in advance, Mike