A research analyst performs database searches for a variety of clients. According to her log, a new search requires approximately 55 minutes. Repeated requests on the same or similar topic take less and less time, as her log shows:
request #: 1 2 3 4 5 6 7 8
time (mins):55.0 41.0 35.2 31.0 28.7 26.1 24.8 23.5
How many more searches will it take until the search engine time gets down to 19 minutes?