Example: Postage Rates

Click here to open an associated Mathcad worksheet:

This example lets you fit a curve to data with an exponential trend.

The following table lists first class postage rates (in cents) together with the year in which the rate took effect. The time frame for this data is more than a century.

Year	Postage (cents)			Year	Postage (cents)
1885	2			1976	13
1918	3			1978	15
1919	2			1981	18
1932	3			1982	20
1958	4			1985	22
1963	5			1988	25
1968	6			1991	29
1971	8			1995	32
1974	10			1999	33

Current postal rates are available from the U.S. Postal Service.