Missing ; before statement

I have the following custom calculation script:

var average = this.getField("Text10").value;

var v = 0;

var fieldName = "fill"; //fields are named time.0, time.1, ...

var s = 0;

var sd = 0;

n = 6; //number of fields

for (var i = 0; i < n; i++) {

    v = this.getField(fieldName + i).value;

    s = s + Math.pow((v - average), 2);

}

sd = ((Math.sqrt(s / n)) / average); //standar deviation

event.value = sd;

event.value = util.printf("%.2f", event.value);

I want the display to be in percentage as opposed to a decimal.  I've tried to just multiply the sd function by 100, but keep getting "SyntaxError: missing ; before statement 13: at line 14.  I can't seem to get this formula correct.

Anyone help here, or is there a better way to display this as a percent?