Acro, alot of companies are winding down their ppc ads for the last few days of the calendar year..I have been tracking this under many key terms and find that the bidding increased and they used up what was left of their ppc budgets and they probably will not resume as normal until next month..so as less companies bid on keywords the rate per click goes down overall..this is normal for the very end of the year as I had a big spike in the middle of the month as companies scurried to spend their remaining budgets on advertising..