Problem with STREAM INPUT for C Program

I'm having a problem with a program I wrote that should show the average number of letters per word after EOF (Ctrl 'Z') is entered. I think the program is reading the input as a stream of characters OK. My average is not working. I'd appreciate if someone could identify where I'm going wrong.

----------------------------------------HERE IS MY CODE-----------------------------------------------

#include <stdio.h>

int main()
{

    int ch; /* some character */
    int count=0; /* count letters */

    printf("Enter input ending with ctrl 'Z' or ctrl 'D':\n");

    ch = getchar(); /* get first input */

    /* loop till eof entered */
    while(ch != -1)
    {

       // check for now space
       if(ch > ' ')
         count++; /* increment count */

       ch = getchar(); /* get next input */
    }

    /* report number of letters */
    printf("Number of letters %d\n",count);


    printf("\n");
    getchar(); /* pause */

    return 0;
}