XBRL Taxonomy Update, March 12, 2018

On March 12, 2018, the EDGAR system was upgraded to Release 18.1 and now supports the 2018 US GAAP, 2018 SEC Reporting (SRT), 2018 Document and Entity Information (DEI), 2018 Exchanges (EXCH), 2018 State and Province (STPR) and 2018 Risk-Return (RR) taxonomies. The 2018 US GAAP financial reporting taxonomy and the 2018 SEC Reporting Taxonomy reflect the same taxonomies that FASB made available on its website on December 21, 2017. The 2018 DEI, 2018 EXCH, 2018 STPR and 2018 RR taxonomies reflect the same taxonomies the staff posted for public comment on October 2, 2017, modified for six elements added to DEI 2018 for voluntary reporting of additional EDGAR submission header data. The registry of unit types was updated to version 2017-07-12 of the XBRL Units Registry (UTR) at http://www.xbrl.org/utr/2017-07-12/utr.xml. Refer to the Release Notes for SEC Taxonomies 2018 for details of the changes (https://xbrl.sec.gov/doc/releasenotes-2018.pdf). The staff does not anticipate that the removals of the 2016 US GAAP, 2013 DEI, 2009 DEI, 2016 EXCH, and 2010 Risk-Return taxonomies will occur before June 2018.

Please see https://www.sec.gov/info/edgar/edgartaxonomies.shtml for a complete listing of supported standard taxonomies.

The Mutual Fund Risk/Return Summary Taxonomy Preparers Guide has been updated for changes to the 2018 RR taxonomy: https://xbrl.sec.gov/rr/2018/rr-preparers-guide-2018-03-12.pdf.

The staff strongly encourages companies to use the most recent version of taxonomy releases for their XBRL exhibits to take advantage of the most up-to-date tags related to new accounting standards and other improvements. The staff suggests that filers consider transitioning to the 2018 taxonomies for the earliest reporting period that ends after March 12, 2018, but not for reporting periods that end before March 12, 2018.