Considering the average hair count per graft on mere mortals is usually around two hairs, consider this: If most, (say 75% of his 2835 grafts which is 2126) as Dr. Keller states, of his grafts were 4 hair grafts that would yield 8504 hairs. Let's say the remaining 709 grafts were single hair grafts. His surgery yielded a total of 9213 hairs which for most folks would equate to around 4606 grafts.
Lucky dog.