Half of all minimum wage earners are young people entering the work force (under 24). Source: BLS.
In 2012, almost two-thirds of minimum wage workers (64.4%) were part-time workers. Source: BLS.
About 2.8% of all workers are paid at or below the minimum wage. Over half of that number are paid below minimum wage. Source: BLS.
Of the 3.6 million people who earned at or below minimum wage in 2012, 2.0 million earned less than the minimum wage. Source: BLS.
---Conclusion raising the minimum wage would only help 1.6 million or 1.2% of the workforce, because those making less than minimum wage are already operating outside of the law.