Trend Projection: When numerical data are available, a trend can be plotted on graph paper to show changes through time. If desired, the trend line can then be extended or "projected" into the future on the basis of the recent rate of change. Such a projection shows where the trend should be at some point in the future assuming there is no shift in the rate of change. Example: A population with a steady 2 percent rate of annual growth will double in about thirty-five years.