Answer
$2003$
Work Step by Step
The apparent slope of the graph seems to be the steepest at $t=3,$ which represents 3 years after 2000.
After this point, the slope becomes "gentler" and starts approaching the horizontal slope.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.