How to measure data transmission rate in XBEE?

HI all,

I am interested in knowing how do we measure the data transmission rate in XBEE modules practically? I understand that the data is less than the specified rate theoretically. I am using XBEE24 and XBEE explorer. I am reading using Processing software data file stored on a PC and sending it to another PC with similar setup for receiving. I wish to know how long it took for the data packets to reach the destination PC?