Estimates vary for the size of the U.S. retirement shortfall, but most agree it is a looming crisis--especially for women, according to Sallie Krawcheck, a former BofA exec.

The average monthly cost of a Medicare Part D plan will rise from $36.68 to $41.46, the largest increase since 2009, according to the Kaiser Family Foundation.

Based on employee demographics and interests, here are seven examples of trending specialty classes that employees love right now.

Older workers are in trouble when it comes to retirement. But it's not too late to do something to boost your retirement plan income.