public static String permillage(double p1, double p2) {
        String str;
        double p3 = p1 / p2;
        if (p1 == 0.0) {
            return "0.00";
        }
        if (p2 == 0.0 && p1 != 0.0) {
            return "-";
        }
        DecimalFormat df1 = new DecimalFormat("0.00");
        str = df1.format(p3 * 1000);
        return str;
    }