Political party funding in the USA

Here's an interesting table, it shows the "Top All-Time Donors, 1989-2010" in the USA. Many interesting figures are exposed but I found interesting that the second highest sum of money over this 20 year period was donated by American Fedn of St/Cnty/Munic Employees. This organisation donated $41,751,311 of which around 98% went to the Democrats. Just like Unison in the UK, public sector workers know who will look after their interests at the possible expense of the Country's interests.