History of the IDL database
The first version of the IDL, launched in 2010, only contained information on the deaths of supercentenarians (at age 110+). The data collected were used to produce “Supercentenarians”, the first monograph on supercentenarians, published in 2010. It emerged that, although these data provided a significant insight into mortality after the age of 110 and a relatively reliable estimation of life expectancy at that age, they did not fill the gap between the oldest ages at which ordinary data were sufficient to provide a good measure of mortality. It was therefore agreed that the database should be expanded to include deaths occurring between 105 and 110 years of age, those of “semi-supercentenarians”.
The current version of IDL therefore includes not only the majority of previously-published data as well as new data collected during successive updates, but also, for a number of countries, the same information for semi-supercentenarians. On the other hand, in 2020, data from certain countries, including Italy and Japan (a part), were provisionally withdrawn from IDL for various reasons.
IDL currently provides information on supercentenarians for 13 countries (11 European countries plus Japan, the United States and one Canadian province, Quebec). The data on semi-supercentenarians are available for 10 countries, with Finland, Sweden, Spain and Japan not yet contributing this data.