Tesla Motors Club

I charge my model 3 to 80%. I have a scheduled departure time of 8:30am. This morning I left a little late, at about 8:50. I came out, and as I was unplugging my car, noticed it was charged to only 77%. (BTW, the second i backed out onto the driveway, it immediately dropped to 76%).

Any thoughts on why I didn't have my full charge?

Thanks