person.cfc

//Person
component {
   static {
       static.instanceCount=0;
   }

   public function init(required String firstName, required String lastName) {
     this.firstName=arguments.firstName;
     this.lastName=arguments.lastName;
     static.instanceCount++; 
   }

   public static numeric function personInstancesCreated() {
       return static.instanceCount;
   }
}