No, just looking at your numbers, it's easy to see that comments increased in last week:
28th week = 138247-30602 = 107645 comments
27th week = 136600-33135 = 103465 comments
So comments increased by about 4%.
Anwyays, the numbers you show above indicate the increase can't be explained by bots. It is hard to see, so I think the best thing to do would be to add a new graph of total comments vs known bot comments.