The president of State University wants to forecast student enrollments for this academic year based on the following historical data:

Year

Enrollments

$5$ Years ago $15,000$

$4$ Years ago $16,000$

$3$ Years ago $19,000$

$2$ Years ago $20,000$

Last Year $,21,000$

What is the forecast for this year using the least squares regression line for these data?

$22,800$

$23000$

$21,000$

$18,750$

$22,600$

$24,600$