The data given below represent the annual gross revenue (N'millions) obtained by a telephone company over the periods 1987 - 1996:
Year Gross Revenue (N'million)
1987 13.0
1988 14.1
1989 15.7
1990 17.0
1991 18.4
1992 20.9
1993 23.5
1994 26.2
1995 29.0
1996 32.8
(a) Plot the data on a graph paper
(b) Fit a least-squares trend line to the data and plot the line on your graph
(c) What are your trend forecasts for the years 1999, 2001, 200, and 2006?