Historical tags


I have a number of discreet tags the give me the status of each loader(calling/active) on a material system, I want to get the utilization % for the system so Created the historian tags, what is the best way to sum the times for each state( on/off). Ive looked at the the SWL table for the tags, it appears that the tags are stored under tag id, how can I find the corrisponding tag names.