No one can give an exact answer because reply rates always depend on four things: your infrastructure, copy, offer, and a clean lead list. If all four are done properly, you’ll get results. But if even one of these is missing, you’ll barely see any leads.
It’s very common for clients to run campaigns for 2–3 months without results, and then come to us to clean and fix everything. So if all the fundamentals are set up correctly, you can definitely expect results.