Zombie Traffic Draining Adwords Budget

Is there anyone else here seeing a very high rate of bad traffic coming from Adwords? My sales have been down since September but my spend is 300%! WTF! I will have one good day in Adwords followed by a series of bad days and the cycle repeats itself. On bad days the people visit the site and view maybe one or maybe two pages and leave. This is not normal traffic and looks like bots, but no abnormal bot activity has been found after examining my logs.

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