I am not sure what statistics will show you.
You need to interview agents. Interview them until you KNOW you have found the right one. Be picky, take your time and don't settle or get pushed into anything.
For the largest purchase of your life (at least for most people), it pays to be picky. The difference between a great agent and a mediocre (or worse) agent is like night and day.
Remember the agent works for you so you have to think of it like they are interviewing for a job, which is in fact what they are doing.
Agents should not only be knowledgeable but they should be willing to answer any and all questions you have thoroughly and patiently. If they don't know the answer, they should say "I don't know, but I will get back to you ASAP" and then do it. They should be flexible (within reason) about working around YOUR schedule.
They should listen to what you say and stick with it. If they don't (say on price) they should explain why. All phone calls and inquiries should be returned on a timely basis.
They should be willing to take you through and explain the process thoroughly from beginning to end.
You need to be able to trust your agent completely and know, without doubt that they are advocating for you.
I hope I helped at least a little.