Three paramedics were comparing their ambulance teams' improved response times.
"Since installing a new satellite navigation system," bragged the first, "we've cut our emergency response time by ten percent."
The others nodded. "Not bad," said the second. "But by using a computer model of traffic patterns, we've reduced our average response time by 20 percent."
Congratulations were exchanged until the third paramedic declared, "That's nothing! Since our ambulance driver passed the bar exam, we've cut our emergency response time in half!"