 was above the high threshold for at least 5 weeks;
     * Orange if above the high threshold from 1 to 4 weeks;
     * Yellow if crossed the epidemic threshold but not the high one;
     * Green if it did not cross the epidemic threshold.
    */
    function alert_level_for_whole_year(d) {
        if (d[4] >= 5) return 4;
        if (d[4] >= 1 && d[4] < 5) return 3;
        if (d[2] >= 1 || d[3] >= 1) return 2;
        return 1;
    }
    
    // Feed it through crossfilter  
    var ndx = crossfilter(data