It's also worth noting for completeness' sake that some routers (a specific example being my Cisco small-business-geared model) provide information through their administration interfaces about how much data has been transferred. Mine can be configured to reset the counters at a specified interval, email reports and implement limits in addition to simply displaying the numbers in its web interface.
I have no idea if the DI-524 specifically has such capabilities, but it might be worth having a look through its administration interface just in case. Since the router is generally restarted much more rarely, it would probably provide relatively useful data, and it also won't be limited to one particular host, which may or may not be of interest.