To estimate the population in 2014, we need to assume that the relation is linear that is the points from 1990 to 2014 forms a straight line. It will have the equation of the form y=mx + b. For this case, b would be zero since at year 0, the population is assumed to be zero. We need to calculate the slope as follows:
m = (139 million - 134 million ) / 2000 - 1990 = 500000
The equation would be:
y = 500000x
Therefore, the population in the year 2014 would be 1007 million.