It really depends on the facility. In one facility I have had about 15-16; on one wing there was odd number of residents and we had the same hallways each day so they would float the resident between two CNAs to "make it fair." There were a total of 4 CNAs, 4 hallways, and about 60 residents in the LTC facility.
In another facility, it was set up completely different from the facility above. This facility had 2 wings with a minimum of 6 CNAs on each wing... I have worked this facility with only 4 CNAs because the could not get people to come in but it REALLY disrupted daily living for the residents and it wasn't fair to them. When there are 6 CNAs in each wing, each CNA is responsible for about 15 to 17 residents. The way this facility is run is you work with another CNA, so 2 people are responsible for 30 or so residents. There were 4 hallways on each wing(2 short and 2 long) so there would be 2 CNAs on a long hallway, 2 CNAs on a long hallway, and 2 CNAs doing the 2 short hallways. This was a really large LTC facility.