For FYE 2012 through the end of 2015 Alphabet's Income After Tax has been, on average, 81% of its Income Before Tax. That implies a 19% average tax rate. Excluding Q4 2015, the same ratio for Q3 2015 through the end of Q3 2016 was 82%. That implies an 18% average tax rate.
The anomaly was Q4 2015, not this most-recent quarter.
The anomaly was Q4 2015, not this most-recent quarter.
Source: Google Finance