Anyone noticed strange AdMob change lately?

Hi all, it's been a few days since I noticed one strange things in my AdMob reports. The number of clicks significantly increased, even up to 20% in some of my apps, while the value of the click dropped significantly to ~0.01 per click. I don't have many apps, and all of them combined don't have more than ~500 impressions/day, but this trend has been lasting for a few days now and is consistent in all my apps. Am I just confused by some statistical anomaly, or AdMob changed it global behaviour? As a side question, which AdMob alternative for Android would you fellow HN users recommend?