Program do przeliczania mpg

Witam wszystkich

//average program with sentinel controlled repition
import java.util.Scanner;

class Milage
{
public static void main (String args [])
{
	Scanner myinput = new Scanner(System.in);

	int Counter;
	int tank;
	int total;
	int milage;

	double average;

	//initialization phase
	total = 0;
	Counter = 0;

	//processing phase
	//prompts to user to input size of tank


	System.out.print("Enter size of you tank in gallons: ");
	tank = myinput.nextInt();
	System.out.print("Enter Your mialage:    -1 to Quit: ");
	milage = myinput.nextInt();

	while (milage != -1)   //check for valid input
	{
	//add grade to total
	total = total + milage;
	//avrmile = avrmile + milage;
	//add 1 to grade counter
	Counter = Counter + 1;


	System.out.print("Enter Your mialage:    -1 to Quit: ");
	milage = myinput.nextInt();
	}
		//display message
		if (Counter != 0)
		{
		average = (double)total/tank;


		System.out.println("The average milage per gallon is: "+average);
		}
	else
		System.out.println("No milage were entered ");
	}
}

Czy ten program jest jezeli chodzi o przeliczenia dobrze napisany ? nie jestem na 100% przekonany.
Z góry dzieki
Pozdrawiam

Wszystko wskazuje na to, że jest źle:
Konkretnie linijka:

average = (double)total/tank;

wg mnie powinna wyglądać tak: average = (double)total/Counter/tank;