Bill Knapp is Des Moines’ indispensable man.

He is the only person named to each of three premier power lists compiled over the last 37 years by local media.

Knapp was No. 15 on The Des Moines Register’s 1976 “Powers That Be” list of the area’s 25 most powerful leaders. When that list was reprised in 1990, Knapp claimed the top spot, edging out John Ruan, who had been No. 1 on the 1976 list.

Now, the Business Record has a new list of the area’s most influential leaders, and this time Knapp is No. 2, behind Bankers Trust Co. chief Suku Radia.

The new list appears in the Business Record’s 2013 Book of Lists, published earlier this month.

It was compiled from a poll of Business Record readers, which makes it more democratic than the Register lists. Those earlier lists were based on interviews with select business leaders.

Actually, the methodology is different for all three lists, which makes comparisons difficult.

Nonetheless, it’s obvious that local leadership is aging.

The average age of people on the 1976 list was just under 54. At that time, investor Joe Rosenfield (No. 8) was the oldest at 72 and then-Polk County Supervisor Tom Whitney (No. 19) was the youngest at 32.

The average age for the 1990 list was 57. John Ruan (No. 2) was the oldest at 75, and Fred Hubbell (No. 7) was the youngest at 38.

The average age on the 2013 list is 61. Knapp (No. 2) is the oldest at 86, while tech entrepreneur Ben Milne (No. 21) is the youngest at 30.

It can be argued that, even as local leadership has aged, it has become more vibrant.

That’s because the 1976 list included seven men who were the second, third or even fourth generation of their families to hold community leadership positions. The 1990 list included only four legacy leaders, and the new list has only two.

It also can be argued that the influence of government has steadily decreased over time.

The 1976 list included four political leaders: Gov. Robert Ray (No. 4), Des Moines Mayor Richard Olson (No. 5), Des Moines City Councilman Russ Lavine (No. 9), and Polk County Supervisor Whitney (19).

Three political leaders were on the 1990 list: Mayor John “Pat” Dorian (No. 13), Polk County Supervisor Richard “Red” Brannan (No. 14), and State Senator and former Des Moines City Councilwoman Elaine Szymoniak (No. 20). Terry Branstad, who had at that point already been governor for seven years, did not make the 1990s top-25 list.

This time, Governor-again Branstad is the only politician on the list, and he is No. 23. No one from city or county government is on the new list.

Meanwhile, two local businesses appear to have extended their influence.

One is Principal Financial Group Inc., which had no representatives on the 1976 list, only one on the 1990 list, but four on the 2013 list – CEO Larry Zimpleman (No. 4), retired chairman J. Barry Griswell (No. 6), chief marketing officer Mary O’Keefe (No. 17) and Daniel J. Houston (No. 20).

Ruan family interests also have a lot of influence. In addition to Radia (No. 1) at Bankers Trust, which is owned by the Ruans, there is Steven Zumbach (No. 3) of the Belin law firm, who serves as outside counsel to the Ruans, Steve Chapman (No. 13) is chief of Ruan Transportation Management Systems Inc. Finally, John Ruan III is No. 14 on the new list.

Comparisons of the lists show a lot of turnover. Only five people from the 1976 list showed up on the 1990 list, while only four from the second list show up on the 2013 list.

And only one made all three list, the indispensable Bill Knapp.

Business Record columnist, Email: daveelbert@bpcdm.com, Phone: (515) 988-3787, © 2013 Business Record