Typically, you add your business phone to your website so that people can call for your service or product. They call and someone answers the phone and that is about it. You could ask them as part of your phone answering script how did they hear about you or something else that might help record some data about the phone call. But, you are missing a lot of information. Your website analytics knows a lot of information about a website visitor. If you change to a pool of phone numbers from a call tracking service, you can link those phone calls to website data to give a great picture of people who call your business.