From 1 All the Way to 100 Terabytes—NLM by the Numbers

We figure it’s not many institutions that can boast the big numbers the National Library of Medicine can. We decided to share a few that keep us busy during the day—and even at night. (Who wants to count sheep when you can count journal citations?)

We’ll start small and work our way up.

oneWe’re #1!

The National Library of Medicine is the world’s largest biomedical library. NLM creates and hosts major resources, tools, and services for literature, data, standards, and more.


threeNLM’s Strategic Plan for 2017–2027 focuses on three main goals that, once achieved, will transform NLM into a platform for biomedical discovery and data-powered health by

1) innovating, building, and sustaining an open ecosystem for health information, biomedical data, and scientific scholarship,

2) optimizing user experience and use of our data, literature, and information resources, and

3) assuring a diverse and growing data-savvy biomedical workforce and data-ready users of NLM resources.

sixteenNLM serves as the primary supporter of pre- and post-doctoral research training in biomedical informatics and data science at 16 universities across the US.



182That’s how old NLM is.

Sometimes people are surprised to learn that we’re older than our “parent,” the National Institutes of Health.

NLM traces its roots back to the founding of the library of the US Army Surgeon General in 1836. More than 100 years and a few name changes later, an amendment to Title III of the Public Health Service Act, the National Library of Medicine Act, placed the Armed Forces Medical Library under the Public Health Service and renamed it the National Library of Medicine on August 3, 1956.


The oldest item in the NLM collection dates back to 1094, making it 924 years old. It’s an Arabic manuscript on digestive diseases.



NLM works in partnership with the 7,026 members of the National Network of Libraries of Medicine (NNLM®) to better provide access to biomedical and health information across the country.



What’s up, DOCLINE?

So far in 2018 (FY), there have been 847,110 requests placed in DOCLINE, NLM’s automated interlibrary loan request routing and referral system. DOCLINE enables the efficient sharing of medical literature and resources among member libraries, routing requests quickly through the National Network of Libraries of Medicine. Currently, 93.3% of requests are filled successfully, and the average time for lenders to fill a DOCLINE request is less than a single day.

25 million
In July, MEDLINE reached a milestone: its 25thmillion journal citation. MEDLINE is the Library’s premier bibliographic database that contains references to journal articles in the life sciences with a concentration on biomedicine. A distinctive feature of MEDLINE is that records are indexed with NLM Medical Subject Headings (MeSH®).

28 million
NLM has nearly 28 million items in its collection. This includes books, journals, manuscripts, technical reports, and audiovisuals.



Now for some really big numbers
Scientists, health professionals, librarians, and the public in the United States and around the world search the Library’s online information resources billions of times each year.

As the world’s largest biomedical library, NLM creates and hosts major resources, tools, and services for literature, data, standards, and more. We send more than 100 terabytes of data to nearly five million users and receive more than 10 terabytes of data from more than 3,000 users every weekday.

If you’re wondering what the heck a terabyte is, you’re not alone. While the name suggests a snack for a T-Rex, a terabyte is a multiple of the unit byte, which is the amount of digital storage required to store a single character of text. “Tera” represents the fourth power of 1,000 or 1012 in the International System of Units. So, one terabyte is one trillion bytes.

4 thoughts on “From 1 All the Way to 100 Terabytes—NLM by the Numbers

  1. Eight!

    Another great number.

    Kathleen and Amanda–Thank you both for commenting.

    Anyone else have a number to share?

  2. Pingback: 2018’s Seasons of Stories from NLM in Focus | NLM in Focus

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