The Internal Revenue Service Restructuring and Reform Act(RRA) was signed in law by President Clinton in 1998. A major objective of RRA was to promote electronic filing of tax returns. Data in table illustrate percentage of individual income tax returns filed electronically for filing years 1998-2006. As percentage P of returns filed electronically depends on filing year y and each input corresponds to exactly 1 output, percentage of returns filed electronically is the function of filing year; so P(y) represents percentage of returns filed electronically for filing year. Determine average of change of percentage of e-filed returns from 1998-2000
Year Percentage fo returns e-filed
1998 20.7
1999 23.5
2000 27.6