State demographer Tom Gillaspy is one of the best-known non-politicians in state government. That's not just because he's led four censuses and advised six governors. He has also addressed an average of three audiences per week for more than 32 years, describing in cogent, witty terms how coming population changes will affect Minnesotans. A big crowd is expected at the Transportation Building cafeteria at 2 p.m. Tuesday to thank and salute Gillaspy on his last day on the job. He's retiring, at age 64. My guess is that he'll give his admirers one more chance to chuckle at his sure-fire laugh line: "I've discovered that on average, people age one year every 12 months."Gillaspy was trained as an economist as well as a demographer, and is an authority on the economic implications of an aging and increasingly diverse state population. As half of the "Two Toms" speaking duo, Gillaspy teamed up with state economist Tom Stinson in recent years to help Minnesotans understand the "new normal" that is dawning in the wake of the Great Recession. (Stinson said last week that their act has not folded.) Gillaspy's analyses, genially delivered in his fading Texas drawl, have brought demographic considerations to bear on a host of state policy questions, from early education to elder care. A sample of his wit can be seen in the only partially facetious "Not Yet Gazette" his office issued in 1994, projecting headlines for 2025. Among them: "Are ElderDorms Homes or Prisons for Old People?" (forecasting a projected surge in poverty among the elderly) and "Minnesota Counties are now down to 42" (forecasting local government consolidation in the face of mounting financial pressure).Gillaspy's successor, Susan Brower, a former research associate with the Wilder Foundation's Minnesota Compass, will be only the third state demographer since the position was created in the early 1970s. The first occupant of the position was Hazel Reinhardt, who went on to a career as a researcher and pollster for this newspaper and a consultant to a host of organizations. Gillaspy followed her vigorous example in office. I'm rooting for him to do the same in retirement, staying visible – and quotable.