Yep, add up miles from all of the years to get a long-term business percentage.

Assuming it is still a gain, you should be good to go.

In the event it were to show a loss, then you need to find out if it was business use immediately after purchase, or if it was converted from personal use.  If it was converted from personal use (and those original numbers we went through shows a LOSS), then you have some more calculating to do.