I've tried to keep track of the 175 orders. It can be difficult because several orders never mentioned which regional would operate the aircraft. The fleet plan for 2016 ends the year with 114 E175's. My guess is that the 2017 fleet plan will have 153 175's as the year end total (the current limit).

My best estimate on the final 175 fleet:
Skywest 58
Mesa 45
Republic 50
Total of 153.