Democracy has been defined and measured in various ways. This article argues that combining two basic dimensions of democracy - competition and participation - can yield a theoretically satisfactory measurement of democracy that employs three measures: degree of electoral competition, degree of electoral participation and a combined index of democratization. These variables have been used in the author's previous comparative studies of democracy. The new dataset combines previous data and extends these to cover the period 1810-1998. That dataset includes 187 contemporary and former independent states from the year 1810 or from the year of independence. In the dataset, original electoral and other political data needed to calculate the values of Competition and Participation variables are given and documented separately for each country. The values of the three variables are calculated and given for each year over the period of comparison. Finally, the new dataset is compared with the Polity98 measures of democracy and the combined Freedom House ratings of political rights and civil liberties.