Air travel on Mountain Airlines for the past $18$ weeks was:

Week Passengers

$1597$

$2599$

$3606$

$4605$

$5607$

$6616$

$7623$

$8618$

$9631$

$10635$

$11632$

$12644$

$13649$

$14638$

$15651$

$16653$

$17657$

$18670$

Use regression to develop a forecast for the expected number of passengers for the next three weeks.