Special needs children in Southern Dallas

I am working on opening a daycare/learning facility for children with physical handicap needs. I desire to open two in the southern portion of Dallas. I am trying to find out how many are in need of daycare. The age range is 0-5 years with before and after school care for their siblings up to 10 years old. They can be mild to severe in physical impairment understanding that some will come with some mental impairment. I would greatly appreciate the information.