birthday probability undesired output

my code below supposes to generate a random days of year and matches every 2 people who have same birthday which also know as birthday problem , the code works but no as desired

public double simulate(int size, int count) {

    Random random = new Random();

    double x[] = new double[size];

    double matches = 0;

    boolean isMatch = false;

    random.setSeed(count);

    for (int i = 0; i < count; i++) {

        for (int j = 0; j < size; j++) {

            x[j] = random.nextInt(365);

            for (int k = j + 1; k < size; k++) {

                if (x[j] == x[k]) {

                    matches++;

                    isMatch = true;

                    break;
                }
            }
            if (isMatch) {

                isMatch = false;
                break;
            }
        }
    }
    return (matches/count)*100;
}

and here is the Expected output result

 simulate(number of people,number of simulation)
 simulate(5, 10000) output = 2.71
 simulate(7, 5000)  output = 5.34 
 simulate(2, 10000) output = 0.27 
 simulate(9, 10000) output = 9.47 
 simulate(30, 20000) output = 70.675
 simulate(15, 50000) output = 25.576
 simulate(35, 50000) output = 81.434
 simulate(45, 50000) output = 94.2

and this what Actual output :

     simulate(5, 10000) output = 2.54
     simulate(7, 5000)  output = 5.64 
     simulate(2, 10000) output = 0.18
     simulate(9, 10000) output = 9.05
     simulate(30, 20000) output = 68.98
     simulate(15, 50000) output = 25.12
     simulate(35, 50000) output = 79.90
     simulate(45, 50000) output = 92.99

thanks for you time .