A new report shows a 21% annual increase in cash balance "hybrid" retirement plans in the United States between 2009 and 2010 (the most recent year for which IRS reporting data is available), almost double the previous year’s 11 percent growth rate. Cash balance plans continued to outpace all other sectors of the retirement plan market, according to the 2012 Cash Balance Research Report from Kravitz, a provider of retirement plan management services.