He has 75 in Rome, 75 in Hamburg, 35 in French Open = drop to about 90 if he defends none of them.
55 in Queens and 35 in Wimbledon = drop to around 110-120
Virtually nothing after that. Basically, every win he gets from now will start getting him back up
I think he can still pass Andy for the Brit #1 place by the year-end.