Study the table given below, which shows the expenditure of the company SRT under different heads from the year 1998 to 2002, and answer the following question?

Year	Procurement	Production	Marketing	Interest on Loan	Tax
1998	185	78	45	23.9	56.3
1999	274	89	56	34.6	62.2
2000	163	95	53	44.8	51.7
2001	252	104	67	37.6	76.9
2002	241	123	49	29.4	84.3

References: year, procurement, production, marketing, interest on loan, tax

The total expenditure on marketing of SRT Company during the given period was approximately what percent of the total expenditure on purchasing?