Is there an easier way to do this if statement?

I'm working on a java program that takes grades inputted gives the total number inputted and the average however I'm having trouble figuring out how to do the highest grade entered currently I"m using a ton of nested else if statements, but there has to be an easy way to do this rather than typing 100 else if statements heres my code. I put a comment where the else if statements begin that determine the highest grade

//Jonathan Towell
//This program will take grade inputs and then display the amount of A's B's C's D's and F's
import javax.swing.JOptionPane;


public class Grades 
{
public static void main(String[] args)
{
    JOptionPane.showMessageDialog(null, "Welcome to Jonathan's Gradebook");
    int A = 0, B = 0, C = 0, D = 0, F = 0;
    int totalGrades = 0, grade = 0, averageGrade = 0, highestGrade = 0;
    while (grade >= 0)
    {
    grade = Integer.parseInt(JOptionPane.showInputDialog("Enter one grade followed by the enter key\n when finished enter -1"));
    if (grade <= 100 && grade >= 90)
    {
        A = A + 1;
        totalGrades = totalGrades + 1;
        averageGrade = averageGrade + grade;
        if (grade == 100) // Determines highest grade
        {
            highestGrade = 100;
        }
        else if (grade == 99)
        {
            highestGrade = 99;
        }
        else if (grade == 98)
        {
            highestGrade = 98;
        }
        else if (grade == 97)
        {
            highestGrade = 97;
        }
        else if (grade == 96)
        {
            highestGrade = 96;
        }
        else if (grade == 95)
        {
            highestGrade = 95;
        }
        else if (grade == 94);
        {
            highestGrade = 94;
        }
    }

    else if (grade > 100)
    {
        JOptionPane.showMessageDialog(null, "No extra credit for this assignment\n please enter a value less than 100");
    }
    else if (grade <= 89 && grade >= 80)
    {
        B = B + 1;
        totalGrades = totalGrades + 1;
        averageGrade = averageGrade + grade;
    }
    else if (grade <= 79 && grade >= 70)
    {
        C = C + 1;
        totalGrades = totalGrades + 1;
        averageGrade = averageGrade + grade;
    }
    else if (grade <= 69 && grade >= 60)
    {
        D = D + 1;
        totalGrades = totalGrades + 1;
        averageGrade = averageGrade + grade;
    }
    else if (grade <= 59 && grade >= 0)
    {
        F = F + 1;
        totalGrades = totalGrades + 1;
        averageGrade = averageGrade + grade;
    }
    }
    averageGrade = (averageGrade / totalGrades);
    JOptionPane.showMessageDialog(null, "Total number of grades entered was " + totalGrades + "\n The average grade was: " + averageGrade + " percent." + "\nA's: " + A + "\nB's: " + B + "\nC's: " + C + "\nD's: " + D + "\nF's: " + F + "\nThe highest grade earned was: " + highestGrade + " percent.");
    System.exit(0);
}


}