Even if you exclude the $2.3 billion unaccounted for, that still leaves $7.7 billion dollars if Alimony payments being claimed on taxes.
As we read further in the highlighted areas, we can see that the IRS doesn't even have accurate methods and provisions to make sure individuals are providing valid Tax Identification Numbers (TIN), thus making them unable to rule in punishments.
The latest data based on the U.S Census, 97% of alimony recipients are women. So we can totally see how alimony is basically scamming men and tax payers out of their money by the billions! Here's the quote:
"Americans gave $9.4 billion to former spouses in 2007, up from $5.6 billion a decade earlier, according to the Internal Revenue Service. Men accounted for 97% of alimony-payers last year, according to the U.S. Census Bureau..."