I've completed processing of the 1 July 2013 data from WorldCat, with all previous reports run for this period:


There are now three snapshots for trend comparison. As you might expect, there is substantial growth with some of the new fields. For example, from April to July the number of 336 fields jumped substantially: <http://experimental.worldcat.org/marcusage/336.html>. These reports also reveal that we have a continuing problem with typographical errors but that also the WorldCat Quality Control team as well as catalogers in the field are having a good effect. For example, with 582,218 records with this field in April 2013, there were 129 occurrences of "rdacontnet". This fell to 50 in July, despite there now being 3,573,817 records with that field.

As always, if there is not a report for a subfield in which you are interested, all you have to do is request it. I change two variables in my script and about 20 minutes later the data goes up on the site.
Roy Tennant
OCLC Research