RE Agents are slow to (or don't) call back

[Andre' Arceneaux]

I notice that about 70% of the calls/emails (I tend to do both with properties I'm interested in) I send out to RE Agents go unreturned, is this typical?? Should I (what I planned on doing anyway) send mailers to owners so they can see offers for themselves???? Or is another approach (something I may be missing) warranted???