No speech -- with the possible exception of an inaugural address -- is more labored over by a president and his senior staff than a State of the Union address. Given that, the words that a president uses in the SOTU matter, and are worth closer examination.

With the help of two linguists and the awesome WaPo developer Kennedy Elliott, we've produced this awesome chart that details how presidents over the past century-plus have expressed themselves in the State of the Union.

A few observations before we get to the chart:

* Talk of the environment peaked in the three decades between 1970 and 2000 -- and has barely been mentioned in the last decade or so.

* The word "Iraq" was never mentioned before George H.W. Bush's 1992 SOTU. He said it 15 times.

* The most times the word "God" has been  mentioned was 18 by Ronald Reagan in 1984

* "We" is used far more than "I".