C program to computer the average of every third integer lying between 1 and 200

Write a ‘C’ program to computer the average of every third integer lying between 1 and 200?

#include <stdio.h>   
int main()
{
	int a,sum=0,count=0;
	float avg;
	for(a=1;a<=200;a=a+2)
	{
		sum=sum+a;
		count++;
	}
	avg=(float)sum/count;
	printf("Average of : %f",avg);
	return 0;
}

Average of : 100.000000