What Greg is saying is that out of the original question, which had 17 people to connect, that 12 people have been connected. 12 divided by 17 = 70.58 or 70.6%.
Greg also has a number of long-standing challenges to connect several different groups of people, and out of all those challenges that he has run, this one happens to be in 7th place based on the 5 people remaining to be connected and 4th place based on the percentage of people connected. (sorry - had to edit to make it more accurate).
Does that help?