The way firms brag about it, you'd think every third lawyer has worked part-time at some point. Whenever I talk to firms about women partners, someone invariably adds, "And did you know she was promoted to partnership after working part-time?"

So is part-time work gaining traction? Not exactly. According to NALP's just released survey, only 6.2 percent of lawyers at big firms work part-time—and the number is trending downward, albeit slightly:

In 2011, nearly all law firm offices, 98 percent, allowed part-time schedules, either as an affirmative policy or on a case-by-case basis, but as has been the case since NALP first compiled this information in 1994, very few lawyers are working on a part-time basis. . . . In 1994, just 2.4 percent of partners and associates were working part-time. By 2011, the number of lawyers working part-time stood at 6.2 percent, after reaching 6.4 percent in 2010.

But here's the curiosity: Despite that downward trend, a steady stream of partners is opting for part-time. "The growth rate of part-time work among partners has been greater, rising from 1.2 percent in 1994 to 3.6 percent in 2010 and 3.5 percent in 2011," reports NALP.

What's more, that uptick is coming from men: "In 2006 almost 72 percent of part-time partners were women. In 2011 that figure was about 66 percent. In 2010 that figure had dropped to 64 percent."

What's going on? Are those hard-driving male partners getting soft?

"Our survey doesn't ask why, so there is no way to know," says James Leipold, NALP's executive director. "It is likely a combination of several factors, including shifting societal norms about gender roles and family, a younger generation of attorneys of both genders seeking more work/life balance, and finally, a group of older partners who, toward the end of their careers, are scaling back and working part-time rather than retiring."

Despite that intriguing development, part-time work remains a female ghetto. NALP finds that women constitute more than 70 percent of the part-timers:

Among women lawyers overall, 13.4 percent work part-time; among female partners, 11.8 percent are working part-time; and among women associates the figure was 10.0 percent. This contrasts with a rate of just 2.7 percent among all male lawyers.

For both sexes, some locations seem more welcoming about part-time arrangement than others. Of the three largest markets—Chicago, Washington, D.C., and New York—the Big Apple is the least receptive. For part-time partners, Chicago has 3.8 percent; D.C., 4.4 percent, and New York, 1.9 percent, reports NALP. For part-time associates, Chicago has 4.9; D.C., 6.1 percent, and New York, 3.4 percent.

As for all U.S. cities, you can probably guess which ones boast the highest percentage of part-timers: places with great coffee or fabulous skiing. You'll find more part-time partners (about 8 percent of partners) hanging out in Portland, Seattle, and San Francisco. Portland also tied with Denver for having a high percentage (over 9 percent) of part-time associates.

But what's the most macho city in the land, where part-time work is strictly for sissies? That honor goes to Birmingham, which reported no male part-timer in either the partner or associate ranks. This Deep South city also had the lowest overall percentage (2.4) of part-time lawyers in the nation. (Question: Is law practice in this city tradition-bound, or is the pace slow enough that part-time work is unnecessary?)

It's a lot of numbers, but the bottom line is that part-time work isn't really catching on—except among the partners.