This report looks at age/time-related data for the teaching force in Illinois public schools now and as they are likely to be in the year 2000. The report also includes a description of reentering teachers and an assessment of the current status of, and future need for, administrative/supervisory personnel. The report answers the following questions: (1) Will the teaching force increase in number in the closing years of the 1990s? (2) Has the teaching force aged significantly in recent years? (3) How will the teaching force change agewise by the turn of the century? (4) What differences are there in the changes that will be unique to Chicago and to downstate? (5) Will there be shortages of teachers or administrators in the foreseeable future? and (6) What are the positive and negative aspects of the changes expected to occur among teachers and administrators by the year 2000? (JD)