Handicap Calculation for Sheri Gazda for Week 16

Week of Rounds Used:		15	14	13	12	11		Total		Average		90%		Rounded to:
Gross Score:		60	60	65	58	63		306		61.20
Hdcp Score (over Par):		24	22	26	21	24		117		23.40		21.06		21

What does this mean? How are handicaps calculated?