Wikipedia:Good articles was initiated on 11 October 2005, with the current nominations system instituted on 10 March 2006. This table gives a monthly overview of article count, and compares it to that for featured articles. Monthly increases are not the same as new listings, since articles may be removed from both the good articles list and featured article status. Also, good articles that become featured articles are removed from the good articles list. Article counts are those stated on the good articles list and featured article list at 0:00 UTC on the listed date. There may be (relatively) small inaccuracies in these data. If the date and monthly increase columns are in bold, this indicates that a GA backlog drive took place during the preceding month.
When comparing the good articles statistics page and the featured articles statistics page, it may appear that the two tables are a month off. They are not; this has to do with how they are set up. The good articles statistics page gives a snapshot at the beginning of every month, while the featured articles statistics page gives a snapshot at the end of every month.
The number of good articles has been rising as a proportion of the total number of articles, while the proportion of articles featured has been relatively stable since 2006. To interpret these figures, note that the total number of articles on Wikipedia rose exponentially for some time, but since about August 2006, article growth rates have stopped increasing, and now (in 2015) article growth is approximately linear rather than exponential. The proportion of GAs is still increasing, and the proportion of FAs remained approximately constant for several years.