Could you help me find data regarding the number of people in the US
with health FSAs (flexible spending accounts) on a quarterly / annual
basis for the last several years?  I guess most helpful would be
something like:

1/2003: xxx
1/2004: xxx
1/2005: xxx
1/2006: xxx
1/2007 (estimate): xxx

If more detail than annual nums is available, that would be welcomed
but is not necessary.

The big season for spending from FSA's is the first calendar quarter;
I am basically trying to find a proxy through with to estimate this
spending in a specific health vertical for 1Q07 relative to the same
quarter in the last couple of years.  The FSA spending growth in this
vertical (Lasik) should somewhat mirror overall FSA growth, which is
why I'm approaching it from this angle.

Thanks very much to whoever is able to find me data on this.