(UNDATED) Several big-name researchers have recently released extensive studies of the state of American religion, and while they provide vivid snapshots of our diverse and fluid faith traditions, researchers could have saved a lot of time and money.

How?

By simply studying the two great maxims of New York Yankees Hall of Famer Yogi Berra: “The future aint what it used to be,” quickly followed by, “You can observe a lot by just watching.”

I’ve spent recent years following the Gospel According to Yogi and observed the pervasive WASPy dominance coming to an end.

Once upon a time in America, the tall-steeple mainline churches—Presbyterian, Congregational, Episcopal, Methodist and Lutheran — represented the religious establishment. Indeed, they were the religious establishment. Nearly every U.S. president except for John Kennedy (and perhaps Barack Obama, depending on who you ask) came out of that tradition, including religious mavericks Thomas Jefferson and Abraham Lincoln.

It was a time when the National Council of Churches — an umbrella group for 35 denominations perched on Manhattan’s Upper West Side in a 1950s-era “God Box” — was the dominant voice in American Christianity. No longer.

American Protestants — mainline, evangelical and black — today number only barely half (51 percent) of the general population. Less than one of five Americans identifies as a member of a mainline church, and one of four is an evangelical. On Monday (March 9), the American Religious Identification Survey (ARIS) found that the percentage of U.S. “Christians” has shrunk from 86 percent to 76 percent in the past two decades.

It won’t be long until Protestants become a minority faith community in the United States. Clearly for them, the future will not be what it used to be.

The U.S. Religious Landscape Survey, produced by the Pew Forum on Religion & Public Life, found that one in four Americans are Catholics, which puts them just behind white evangelicals (though Catholics are the largest single bloc of believers). While the Catholic percentage has remained fairly constant over time, the demographics have radically changed. More than a third of today’s Catholics are Hispanics, and that number is only going to grow because of immigration.

Not every Hispanic immigrant is a Catholic or remains within in the Catholic Church, but without the massive influx of newcomers, the Catholic population today would be far smaller than it was just three decades ago. In many ways, the new Hispanics are replacing the descendents of Irish, Italian and Polish immigrants who left.

In short, the Catholic future in the U.S. is less St. Patrick and more Virgin of Guadalupe; fewer polkas and more sambas and rumbas.

Muslims, meanwhile, account for 0.6 percent of all Americans, despite some attempts to inflate their numbers. They’re about one-third the size of American Jews, and the key to Jewish demography is the term “religiously affiliated.”

Many Jews — perhaps millions of them — are ethnically Jewish, but not members of a synagogue. My own version of a Yogiism is a phrase I have heard hundreds of times: “Oh rabbi, I’m not religious, but I am very Jewish in my heart.”

Reform Jews now outnumber Conservative Jews, and the smaller Orthodox movement is growing, thanks in part because it offers a reliable religious anchor in a stormy sea of uncertainty. Perhaps the future of American Judaism will be reduced to a choice between Orthodoxy and Reform, with Conservatism a possible target of merger or acquisition by one side or the other.

The biggest news emerging from the recent surveys, however, is something I have long observed: the extraordinary rise in the number of Americans — about 15 percent — who are not affiliated with any religious community. That figure has doubled — doubled! — in just 20 years, and the ARIS study found that the “Nones” are the only religious group that is growing across all 50 states.

Much of that growth has been among the 18-29 set. I don’t need to tell you what that means for the future.

My final observations: the future will belong to those gifted and creative religious leaders — both clergy and lay — who can best adapt to the changing American religious landscape, and effectively recast their often hidebound institutions.

Reading the Gospel According to Yogi probably wouldn’t hurt either.

(Rabbi Rudin, the American Jewish Committee’s senior interreligious adviser, is the author of “The Baptizing of America: The Religious Right’s Plans for the Rest of Us.”)