The table below gives the population in a small coastal community for the period 1990 - 1999. Figures shown are for January 1 in each year.

  Year  1990199119921993199419951996199719981999
  Population  6108591309157416191477961836776742

(a). What was the average rate of change of population between 1991 and 1994?

(b). What was the average rate of change of population between 1995 and 1997?

(c). For what period of time was the population increasing?
From to

(d). For what period of time was the population decreasing?
From to
Note: For (c) and (d), give the starting and ending years for the periods where the population was increasing/decreasing.