According to the U.S. Department of Labor and U.S. Bureau of Labor Statistics December 2010:
As you read this, over 12,000 baby-boomers are leaving the workforce daily. Most due to age, many due to reductions.
This leaves us with a shortfall of over 42 million people in the workforce, 8 million of which are professionals.
Gen-X is not making up the difference simply because Gen-X is half the size of the Boomer generation.
Gen-Y/Millennials are nearly as big as the baby-boomers but it will take another 3-5 years before they are ready to take their place.