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Key MEDLINE® Indicators

  FY2014% ChangeFY2013% ChangeFY2012% ChangeFY2011% ChangeFY2010% Change
Citations Indexed for MEDLINE
765,850 +4% 734,052 -3.5% 760,903 +5% 724,831 +4% 699,420 -1.9%
MEDLINE/PubMed® Searches1
TBA TBA 2.5 Billion +14% 2.2 Billion +22% 1.8 Billion +13% 1.6 Billion +23%
Sub-Total: Web3
TBA TBA 932 Million 0% 932 Million +6% 879 Million +9% 808 Million +5%
Sub-Total: API3
TBA TBA 1.6 Billion +23% 1.3 Billion +36% 956 Million +24% 771 Million +50%
Gateway Searches4
---- ---- ---- ---- ---- ---- 874,000 -27% 1.2 Million -25%
Journal Titles in MEDLINE
5,6478 +0.1% 5,6408 +0.1% 5,633 +1% 5,559 +1% 5,484 +2%
Journal Titles in
Index Medicus6
5,1188 +1% 5,0678 +0.8% 5,025 +2% 4,946 +2% 4,866 +2%
Total Citation Data Creation
981,783 +6% 926,479 +6% 875,576 +4% 845,948 +10% 767,470 +3%
OCRed Citations
55,222 -8% 60,019 -4% 62,562 -12% 71,145 -8% 77,309 -12%
Citations Received
Electronically via XML
926,561 +7% 866,460 +7% 813,014 +5% 774,803 +12% 690,161 +4.5%
Retraction Notices
373 -9% 410 +18% 348 +37% 2545 +15%5 221 +0.5%
Retracted Articles
400 -14% 467 +25% 375 +38% 2715 +12% 243 -2%
Partial Retraction Notices7
0 -100% 3 +200% 1 0% 1 -86% 7 +40%
Partially Retracted Articles7
0 -100% 3 +200% 1 0% 1 -86% 7 +40%
Errata
9,602 +5% 9,178 +13% 8,142 +4% 7,870 -7% 8,433 +15%
Comments
56,652 +16% 48,714 +31% 37,158 +6% 35,049 -2% 35,688 +6.5%
Gene Indexing
78,491 -8% 85,429 -4% 88,944 +11% 80,297 +0.3% 80,042 -3.5%

See also additional MEDLINE statistics.

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

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

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

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.
8The small net increase 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.


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