Out of the two bar graphs provided below, one shows the amounts (Rs in Lakhs) invested by a company in purchasing raw materials over the years and the other shows the values (Rs in Lakhs) of finished goods sold by the company over the years. What was the difference between the average amount invested in raw materials during 1997 to 2000 and the average value of sales of finished goods during the same period 1997 to 2000?