The medical situations are quite different, but in-home accidents, nerve degeneration and cancer are not at all unusual for Americans of their age.

And people of their age are not at all unusual in a Senate where 23 members are products of the Silent Generation, those too young to have fought in World War II but born before that war ended. California Democrat Dianne Feinstein, whose 82nd birthday was Monday, is the oldest in this cohort, which has a ratio of 13 Republicans to 10 Democrats that almost exactly mirrors the partisan divide in the whole Senate.

The eldest group far outnumbers the 17 senators belonging to Generation X, into which most demographers would place those born between President John F. Kennedy’s death in 1963 and President Ronald Reagan’s inaugural in 1981. Having recently turned 38, just eight years older than the constitutional floor, Arkansas freshman Tom Cotton is the youngest of these younger senators, who skew 2-to-1 Republican.

The other 60 senators all were born during the Baby Boom.

Altogether the Senate’s average age when the 114th Congress began in January was almost precisely 61 years — not quite the oldest ever, but a continuation of one of the more interesting trends in congressional demographics. After a 20th-century low of 52 years and six months back in 1981 (thanks to the arrival of a modern record 18 freshmen), the average senatorial age has climbed steadily, crested 60 for the first time a decade ago and has remained above that milestone ever since.

The reality that the Senate is as gray as it’s ever been doesn’t quite square with the popular perception. That’s that the place must be getting a younger vibe thanks to the recent series of wave elections, the retirements of so many prominent long-timers and the last four deaths of sitting senators — at an average age of 87. (All were Democratic icons: Edward M. Kennedy of Massachusetts in 2009, Robert C. Byrd of West Virginia in 2010, Daniel K. Inouye of Hawaii in 2012 and Frank R. Lautenberg of New Jersey two years ago.)

It is true that the average age of a newly elected senator has dropped six and a half years, to 50 years and eight months, just since the middle of the previous decade. But it’s also true that, at quick glance, during that same time almost as many elder statesman have arrived as political meteors. The class up for re-election next year, for example, includes both Democrats Joe Manchin III of West Virginia and Richard Blumenthal of Connecticut, each veterans of statewide politics first elected to the Senate when they were old enough to take Social Security, and Republicans Mike Lee of Utah and Marco Rubio of Florida, each elected before they turned 40.

In addition, there has been a steady increase in the percentage of senators with previous service in elected office — the sort of career path likeliest to postpone ascent to the pinnacle of legislative power in Washington. Twenty years ago, 16 members of the Senate had never been elected to anything else. Ten years ago, that number was 12. And this year, it’s down to eight.

Finally, there remains no shortage of senatorial elder statesmen. Five senators have been in Congress for a majority of their time on earth and two more — Republicans Orrin G. Hatch of Utah and Charles E. Grassley — will pass that “congressional half-life” milestone by the time their current terms expire.

Those expecting the Senate’s aging trend will soon start a reversal can point out that four of the five senators retiring next year (Rubio’s the exception) will be 73 or older when the next Congress begins. But they almost surely won’t be the only ones departing. The average age of the eight incumbents looking at the most competitive races will be 59 next fall, and half are expecting general election opponents older than they are — in three cases, by a decade or more.

Life expectancy in the United States is now just under 79 years, fully a decade longer than the statistically predicted lifespan was during the middle of the 1950s, when the “typical” senator was born. That means only six of today’s senators have lived (and are still working) beyond what actuarial tables say is the norm: Feinstein, Grassley, Hatch and Republicans Richard C. Shelby of Alabama, James M. Inhofe of Oklahoma and Pat Roberts of Kansas.

Each holds a secure place among the most legislatively influential senators of this Congress. Like Reid, Isakson and King, none of them is signaling any interest in popping the political or intellectual clutch this year or next. All are examples of the adage that “age is just a number” — and maybe a less important one than so many of the figures that drive the Capitol conversation each day.

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