Marks of 4 students are given in the table. All the marks are out of 100. Taking all the six subjects together, approximately how much total percentage has been scored by Ravina?

Student Name	Marks
	Hindi	English	Social Science	Science	Mathematics	Computer
Kavita	84	82	74	90	94	90
Anuradha	62	74	70	60	80	55
Anchal	56	60	64	55	68	62
Ravina	80	78	84	70	85	70