4. The projected rate of oil production in the non-Communist countries up to the year 2020 is shown below. Assume this projection is correct (a) Estimate the amount of oil that would be produced (1975, 2015]. Show graphically this 30 25 20 15 10 975 1985 1995 2005 2015 years (b) Determine the average rate of production between 2000 and 2015. Show graphically this 30 25 15 5 1975 19SO 1985 190 1995 220ã2005 201ã2015 201ã years ond 52