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Key MEDLINE® Indicators

  FY2016 % Change FY2015 % Change FY2014 % Change FY2013 % Change
Citations Indexed for MEDLINE 869,666 +8% 806,326 +5% 765,850 +4% 734,052 -3.5%
MEDLINE/PubMed® Searches1 3.2 Billion +14% 2.8 Billion +4% 2.7 Billion +8% 2.5 Billion +14%
Sub-Total: Web3 853 Million -6% 910 Million +1% 900 Million -3% 932 Million 0%
Sub-Total: API3 2.8 Billion +21% 1.9 Billion +6% 1.8 Billion +13% 1.6 Billion +23%
Journal Titles in MEDLINE 5,6238 +0.1% 5,6188 -0.5% 5,6478 +0.1% 5,6408 +0.1%
Journal Titles in
Index Medicus6
5,1368 +0.3% 5,1238 +0.1% 5,1188 +1% 5,0678 +0.8%
Total Citation Data Creation9 1,020,678 +16% 879,709 -10% 981,783 +6% 926,479 +6%
OCRed Citations 39,051 -11% 43,864 -21% 55,222 -8% 60,019 -4%
Citations Received
Electronically via XML
981,627 +17% 835,845 -10% 926,561 +7% 866,460 +7%
Retraction Notices 64110 -4%10 66610 +41%10 4735, 10 +15%5, 10 410 +18%
Retracted Articles 66410 -3%10 68410 +37%10 5005, 10 +7%5, 10 467 +25%
Partial Retraction Notices7 ---- ---- 4 +400% 0 -300% 3 +200%
Partially Retracted Articles7 ---- ---- 4 +400% 0 -300% 3 +200%
Errata 8,992 -27% 12,344 +29% 9,602 +5% 9,178 +13%
Comments 47,906 -9% 52,921 -7% 56,652 +16% 48,714 +31%
Gene Indexing 86,458 +3% 83,734 +7% 78,491 -8% 85,429 -4%

 

See also additional MEDLINE statistics.

Prior Years:
2010-2012
2005-2009
2000-2004
1996-1999

The U.S. Government Fiscal Year (FY) runs from October 1 - September 30.

Not all footnotes apply to archived years.

Note:  See Errata Fact Sheet for definitions. NLM began to report retracted articles separately in FY2003. Prior to that the numbers reported were Retraction Notices only.

Note:  See Gene Indexing and Entrez Gene. Gene indexing began to be phased in during 4th Quarter FY2001 (Jul-Sep) with several hundred links. In 2005, gene indexing changed from LocusLink, where 10 organisms were in scope, to Entrez Gene, where more than 1,800 organisms are in scope. In 2007, gene indexing was applied to more clinical genetics articles.

1Statistical gathering method refined in FY2009.
2June 2007 implementation of Entrez 2.0 ("portals") resulted in changes to the statistical gathering process. FY2008 represents a new baseline for the data and cannot be compared to FY2007.
3Sub-Total labels changed for FY2012 from "Web/Interactive" to "Web" and from "Scripts/E-Utilities" to "API" (Application Programming Interface).
4FY2011 is last full reporting year for the original NLM Gateway; it was transitioned to a new pilot project containing two databases in December 2011. See Reminder: NLM Gateway Changing for additional information.
5Corrected from previously reported numbers:

  • FY2008 Gateway Searches previously 998 Million
  • FY2008 Total Citation Data Creation previously 726,097

  • FY2011 Retraction Notices previously 267 and +21%
  • FY2011 Retracted Articles previously 273

  • FY2014 Retraction Notices previously 373 and -9%
  • FY2014 Retracted Articles previously 400 and -14%

6 Index Medicus® was a monthly bibliographic listing of current biomedical references derived from MEDLINE. The item remains an online indicator in MEDLINE citations found in PubMed. Index Medicus® ceased in print after December 2004 edition.
7 NLM began to report partial retractions separately in December 2006; discontinued in September 2016. All past and future partial retractions are handled as errata.
8The small net increase or decrease results from identification of journals that have ceased publication or for which NLM is no longer receiving citation data electronically; it does not mean that fewer new journals were recommended for indexing.
9Includes PubMed citations that are in these subsets [sb]: inprocess [sb], MEDLINE [sb], OLDMEDLINE [sb], and PubMednotMEDLINE [sb] (completed out-of-scope). Does not include PubMed citations that are publisher [sb]; these are the ahead-of-print, author manuscripts, and Bookshelf-derived citations.
10For Retraction Notices, statistical gathering method changed to count the number of links made between Retraction Notices and Retracted Articles during the fiscal year for any citation in PubMed (not limited to MEDLINE journals); previously, NLM counted the number of Retraction Notice citations completed during the fiscal year. For Retracted Articles, the count has always been the number of citations referenced by the Retraction Notices, regardless of whether a citation for the original paper exists in PubMed.


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