Historically Conor. 189 194 and the record 196 as opposed to 190 and 193.
It should be taken into consideration that Ronda's elevation to superstardom coincided with 190 which iirc did around the same numbers as 189, but with a complete bum opponent and not even a fraction of the marketing at UFC's own expense. Prior to 193 no one gave a good shot to and barely even knew Holly ( who only had credentials from her previous sports, now coming off of a wholly unimpressive dec wins ) and still Honda got massive numbers. That said I think had Ronda won and gone on to face Cyborg at 200, she would have eclipsed anything Conor would have brought in facing Lawler or defending at LW. Had McGregor/GSP materialised then idk.
Right now, I think Ronda's return will be the biggest buyrate in history unless it keeps tallying to 2020 against a nobody. McGregor isn't on that superstar mainstream level, and that's reflected on twitter followers and facebook likes. At the end of the day it looks like Ronda brought more eyes to the UFC and McGregor has got and kept them paying since.