Populations generally increase as an exponential function. In a short period of time, it could be approximated as linear (first degree). Depending what your teacher expects,
Linear model:
rate of increase = (y2-y1)/(x2-x1)=(103-98)/(2001-1994)=5/7 million per year.
From 2001 to 2018, there are 17 years. So add 17(5/7) millions to population of 2001.
exponential model:
Over 7 years, the ratio of populations is 103/98, so the annual ratio is (103/98)^(1/7)=1.007134, about 0.7134%.
Use the compound interest formula to find the population growing at the same rate from 2001 for 17 years:
population at 2018 = 103 millions * 1.007134^17 which is a little over 116 millions.
