(miamiherald) As property values have plummeted by an average of 50 percent, such strategic defaults now make up a sizable chunk of South Florida's foreclosures. In the fourth quarter of last year, they accounted for an estimated 28 percent of all defaults in Miami-Dade and Broward counties, according to recent research from the credit bureau Experian and Oliver Wyman, a New York-based international consulting firm. That's up from 8 percent in the same quarter two years ago. With property values down even further now, researchers are certain the numbers have risen even more. With the social stigma of foreclosure eroding, experts say it is becoming easier for discouraged borrowers to justify throwing in the towel. ``People are saying, ` Everyone is doing this, and I do not feel any compunction in fashioning my own bailout,' '' said Roy Oppenheim, a Weston real-estate and foreclosure defense attorney who conducts weekly seminars that discuss strategic defaults and other financial options for distressed borrowers. South Florida is already a veritable Atlantis of underwater borrowers. In September, homeowners here collectively owed .7 billion more than their homes were worth, according to an analysis by First American CoreLogic. The analysis found that about half of all outstanding mortgages in Miami-Dade and Broward are underwater.