Require javascript formula to determine percentage in Acrobat DC Pro form

For the case of the number of employees being non-zero, I would divide the number of attendees by the number of employees. I would set the field format to the percentage display format and specify the number of decimal places to display. Acrobat JavaScript considers division by zero to result in Not a Number or NaN. One can only use the Custom JavaScript calculation method.

// get computational  values;

var nAttendees = this.getField("Text4.0").value;
var nEmployees = this.getField("Text4.1").value;

event.value = 0;

// clear result field;

if(nEmployees != 0){

// compute if divisor not zero;
event.value = nAttendees / nEmployees
}