Congress's vocabulary falls a full grade level in seven years

Nicko from the Sunlight Foundation writes,

The U.S. Congress speaks at nearly a full grade level lower than it did seven years ago, according to a new Sunlight Foundation analysis. Using the CapitolWords.org website -- which features the most popular words and phrases in the Congressional Record since 1996 -- Sunlight reviewed the vocabulary and sentence structure of what members of Congress are saying.
Today's Congress speaks at about a 10.6 grade level, down from a high of 11.5 in 2005. By comparison, the U.S. Constitution is written at a 17.8 grade level, the Federalist Papers at a 17.1 grade level and the Declaration of Independence at a 15.1 grade level. The Flesch-Kincaid test was used to conduct the analysis, which equates higher-grade levels with longer words and longer sentences.
A complete database of how each member in the current Congress ranks in the analysis is available. The analysis, written by Senior Fellow Lee Drutman in collaboration with Software Developer Dan Drinkard, is broken into three parts on the Sunlight blog:
* Summary and 'report card' infographic
* Full analysis and complete methodology
* Congressional use of top SAT vocabulary words
Top Five
* Rep. Daniel Lungren (R-CA) -- 16.01
* Rep. Lucille Roybal-Allard (D-CA) -- 14.94
* Rep. Jim Gerlach (R-PA) -- 14.19
* Rep. Thomas Petri (R-WI) -- 14.19
* Sen. Daniel Akaka (D-HI) -- 14.18
Bottom Five
* Rep. John Mulvaney (R-SC) -- 7.95
* Rep. Rob Woodall (R-GA) -- 8.02
* Sen. Rand Paul (R-KY) -- 8.04
* Rep. Sean Duffy (R-WI) -- 8.09
* Rep. Tim Griffin (R-AR) -- 8.13

Is Congress getting dumber, or just more plainspoken?

It should be noted that the Constitution was written at a 18th grade level while those spouting off about it today are on a 8th grade level ... see the disconnect? We're going with dumber.