There's only a small increase in the number of comments relative to the number of posts, but in absolute terms the number of comments is also decreasing. It could be bots staying active, but I don't have a chart of that right now.
Total comments on posts yesterday: 15,878
Accounts with most comments yesterday:
@hivebuzz 1376
@beerlover 370
@pizzabot 343
@poshtoken 276
@ecency 271
@luvshares 242
@actifit 170
@hk14d 159
@u89gw 159
@w95hj 158
@vmn31 158
@wiv01 158
So quite a lot of bots...
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.