Using if else condition to compare the result

Question

Hi,
m calculating the percentage of education expenses with monthly income:

public static decimal per_edu;
int h, i;

public decimal edu_percent()
        {

            h = Convert.ToInt32(edubox.Text);
            i = Convert.ToInt32(inctotal.Text);
            per_edu = (h / i) * 100;          
            return per_edu;
        }
Actualy m executing this method on score button it's calculating score and per_edu simultaneously. within a score method, m using per_edu var in an if else condition so is it wrong?? its like ds within a score method:

if (per_edu <= 5)
            {
                scor7 = Convert.ToInt32(1);
            }
            else if (per_edu >= (decimal)(5.1) && per_edu <= 10)
            {
                scor7 = Convert.ToInt32(2);
            }
            else if (per_edu >=  (decimal)(10.1) && per_edu <= 15)
            {
                scor7 = Convert.ToInt32(3);
            }
            else if (per_edu >=  (decimal)(15.1) && per_edu <= 20)
            {
                scor7 = Convert.ToInt32(4);
            }
            else if (per_edu >=  (decimal)(20.1))
            {
                scor7 = Convert.ToInt32(5);
            }
            textBoxedu.Text = scor7.ToString();
But it's showing only zero for per_edu, i hav checked the datatypes of all var. i couldnt fix it. please anyone guide in this.
Regards,