Linear trendline to forecast data

[tjaques]

I have a simple chart showing calls by day average.
Year
1990=100
1995=200
2010=400
2014=515

I want to create a simple line graph and add a trendline showing what calls might be in 2025. Help please. I think I'm over thinking this!

 

[thisoldman]

This is simple and quick. It may be all you need.

Year	Calls
1990	100
1995	200
2010	400
2014	515
2025	#N/A

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</tbody>

Select the entire block and insert a scatter(xy) chart. Then add your trendline.

A line chart would distort the horizontal scale, an xy-chart gives a properly spaced scale.
Excel won't plot the #N/A value in an xy-chart.
You have to include x-values up to or beyond the last point to be displayed on the chart. So you have to include the year 2025.