What is the best way to optimize a function with many if-else statements(multiple conditions)?

What is the best approach or design pattern to optimize the code below?(I've thought about using switch statement but switch statement cannot handle multiple conditions in a single case.)

Below is the code snippet. Each major is determined by a certain numerical range.

public String getMajor(String major) {
    crnCompare = Integer.parseInt(major);
    if ((crnCompare >= 90702 && crnCompare <= 90733) || (crnCompare >= 10004 && crnCompare <= 10037)) {
        this.major = "AC";
    } else if ((crnCompare >= 10087 && crnCompare <= 10108) || (crnCompare >= 10471 && crnCompare <= 10482) || (crnCompare >= 90024 && crnCompare <= 90071)) {
        this.major = "CS";
    } else if ((crnCompare >= 10109 && crnCompare <= 10158) || (crnCompare >= 90072 && crnCompare <= 90116)) {
        this.major = "EC";
    } else if ((crnCompare >= 90117 && crnCompare <= 90203) || (crnCompare >= 10075 && crnCompare <= 10213) || (crnCompare >= 10498 && crnCompare <= 10572)) {
        this.major = "EN";
    } else if ((crnCompare >= 10038 && crnCompare <= 10040) || (crnCompare >= 10214 && crnCompare <= 10255) || (crnCompare >= 10256 && crnCompare <= 10260) || (crnCompare >= 90017 && crnCompare <= 90203) || crnCompare == 11172) {
        this.major = "FI";
    } else if ((crnCompare >= 90670 && crnCompare <= 90790) || (crnCompare >= 11236 && crnCompare <= 11239)) {
        this.major = "FS";
    } else if ((crnCompare >= 90253 && crnCompare <= 90273) || (crnCompare >= 90734 && crnCompare <= 90769) || (crnCompare >= 90274 && crnCompare <= 90360) || (crnCompare >= 10261 && crnCompare <= 10393)) {
        this.major = "GB";
    } else if ((crnCompare >= 100394 && crnCompare <= 10429) || (crnCompare >= 90361 && crnCompare <= 90398)) {
        this.major = "GLS";
    } else if ((crnCompare >= 10430 && crnCompare <= 10451) || (crnCompare >= 90399 && crnCompare <= 90420)) {
        this.major = "HI";
    } else if ((crnCompare >= 10452 && crnCompare <= 10468) || (crnCompare >= 90422 && crnCompare <= 90436) || crnCompare == 11119) {
        this.major = "IDCC";
    } else if ((crnCompare >= 9437 && crnCompare <= 90438) || (crnCompare >= 10469 && crnCompare <= 10470)) {
        this.major = "IPM";
    } else if ((crnCompare == 90421) || (crnCompare >= 11280 && crnCompare <= 11426)) {
        this.major = "ID";
    } else if ((crnCompare >= 90439 && crnCompare <= 90448) || (crnCompare >= 90483 && crnCompare <= 90497)) {
        this.major = "LTF";
    } else if ((crnCompare >= 90504 && crnCompare <= 90535) || (crnCompare >= 10573 && crnCompare <= 10596) || crnCompare == 90785) {
        this.major = "MG";
    } else if ((crnCompare >= 90536 && crnCompare <= 90553) || (crnCompare >= 10598 && crnCompare <= 10616) || crnCompare == 10740) {
        this.major = "MK";
    } else if ((crnCompare >= 90449 && crnCompare <= 90503) || (crnCompare >= 10514 && crnCompare <= 10564) || (crnCompare == 11120) || (crnCompare == 10555) || (crnCompare == 11127)) {
        this.major = "MA";
    } else if ((crnCompare >= 10637 && crnCompare <= 10715) || (crnCompare == 11142) || (crnCompare == 10739) || (crnCompare >= 90575 && crnCompare <= 90622)) {
        this.major = "NAS";
    } else if (crnCompare >= 90554 && crnCompare <= 90574 || crnCompare == 10617 || crnCompare == 10636) {
        this.major = "ML";
    } else if ((crnCompare >= 90623 && crnCompare <= 10646) || (crnCompare >= 10671 && crnCompare <= 10696)) {
        this.major = "PI";
    } else if ((crnCompare == 90647 || crnCompare == 90649) || (crnCompare >= 10697 && crnCompare <= 10698) || crnCompare == 10756) {
        this.major = "PRS";
    } else if ((crnCompare >= 11341 && crnCompare <= 11420)) {
        this.major = "SL";
    } else if ((crnCompare >= 90650 && crnCompare <= 90668) || (crnCompare >= 10716 && crnCompare <= 10734)) {
        this.major = "SO";
    } else if ((crnCompare == 10735)) {
        this.major = "ST";
    }

    return this.major;
}