" 
 ::::As the first tier these ""types of data"" are normally accumulated to detect trends, they say something about the reliability over time. Maybe its not reliable in the ways how wikipedia views it, as an idle time-stamp measurement. What I'm trying to say here, it that the accumulation of data creates the so-called ""reliable sources"" needed for wiki. only difference is that a ""wiki-reliable"" source has done the work for you.   "