A good response rate is anywhere between 15% - 25%. This will depend on the quality of your contact list, the frequency you are making contact with contacts, and the quality of your follow-up message.
If you're getting less than 15% response rates, you should take a closer look at your campaign. It could be a low-quality list or other factors. When in doubt, contact the Customer Success team. They will be happy to help you troubleshoot your low-performing campaign.
You can see your current response rate by logging into your Agent Legend account and viewing the Response Rate widget on your Dashboard. You can also go to particular campaigns to see response rates per campaign.