It is possible the latest crawler has some changes in the crawled URLs which have resulted the number of records being extracted.
To check this, proceed to the crawler admin console under the "overview" page. In the "Last complete crawl" section, click the "Compare with previous crawl". After clicking this button, you should be able to see a comparison view of the current and last crawler status. Then check in the "Monitoring" section to see the change of status.