Seattle residents on Tuesday overwhelmingly decided to shift the way they elect city councillors. They used to do it like us, now they're going to do it like everybody else.

Turns out, Portland is one of two lonely castaways on the ever-shrinking Island of At-Large Elections.

At least among the country's largest 33 cities, only Portland and good old Columbus, Ohio, (a town I've lived in, and enjoyed) still have a city council where all members represent the entire city. That's down from 5 last year, according to a recent study by a University of Washington grad student, and 16 in 1970. Of the 74 American cities with more-than 250,000 residents, only six now use all at-large councils, the study says.

This chart will help give you an idea. It doesn't include cities with over 1 million residents, none of which has an all at-large council. (Note: Austin and Detroit are already moving away from the system).

Ours is a dying way of life, and for some fairly compelling reasons. Seattle's oncoming system has its share of detractors. But research, including the UW study, suggests district-based elections cost far less to run than citywide races—about $76,000 less in fact. They attract less monied special interests, encourage more-diverse candidates and, depending on the layout of the city, can help ensure minority groups are represented by one of their own.

"Where everybody’s at large, it’s really hard to win a city council seat unless you can raise a large amount of money," says rookie City Commissioner Steve Novick, who raised more than $260,000 for his relatively uncompetitive race. "That's a problem."

Novick made clear he's not endorsing a change in Portland's system, but he said such a change—or a robust public campaign financing policy—would make council races more realistic for people without serious political and financial ties.

Hit the jump to see a table detailing expenditures for council elections in various cities.