Update MACIMIDE Global Expatriate Dual Citizenship Database

There is a new 2019 version of the MACIMIDE Global Expatriate Dual Citizenship Dataset. Version V4.00 of the MACIMIDE Global Expatriate Dual Citizenship Dataset now contains data from 1960-2019 and an updated codebook. In 1960, acquiring other citizenship led to automatic loss of citizenship in more than 60% of countries; in 2019 this number is down to 26%. https://macimide.maastrichtuniversity.nl/dual-cit-database/