public calculateCHCS(): number {
    // ch_cs= Percentage change in cash sales = [ cashsales(t) / cashsales (t-1) ]-1 ;
    // where cashsales= Sales  - Accounts Receivable

    const cashsalesCurrent: number = this.currentYear.revenues - (this.currentYear.receivablesNet - this.prevYear.receivablesNet);
    const cashsalesPrev: number = this.prevYear.revenues - (this.prevYear.receivablesNet - this.prevPrevYear.receivablesNet);;

    const ch_cs: number = (cashsalesCurrent / cashsalesPrev) - 1;

    return ch_cs
}