2020-02-08:  Ecdat 0.3-6 adds variables popM, popYr, GDP_B, and GDPyr to data set "nuclearWeaponStates".  

2019-12-05:  Ecdat 0.3-5 corrects the description of Crime$density to read, "hundreds of people per square mile" from "people per square mile".  Thanks to Yungfong "Frank" Tang for identifying this error and confirming the needed correction.  

2019-11-05:  Ecdat 0.3-4 adds variable 'firstTestYr' to 'nuclearWeaponStates'.  It also corrects an error in the 'Mroz' data set, in that "work" had the names of the levels incorrectly swapped.  

Ecdat 0.3-3 adds data set "nuclearWeaponStates", which might be used to model the probability distribution of the time to the next new nuclear weapon state.  