Beyond Google: The Invisible Web: Fast Facts

2001:

• Even the best search engines can access only about 16% of the available information on the World Wide Web. Therefore 84% of the information is excluded. That 84% has become known as the Invisible Web.
•  Put another way, the size of the Invisible Web is 500 times larger than the Surface Web.
• The Invisible Web contains nearly 550 billion individual documents as compared with the Surface Web's 1 billion.
• The Invisible Web is the largest growing category of new information on the Web.
•  95% of the Invisible Web is publicly accessible information.
• More than half of the Invisible Web resides in topic specific databases.
  (Bergman 2001)

2003:

• Surface Web: 167 terabytes
• Deep Web: 91,850 terabytes
  (Lyman 2003)

2006:

• Academic Invisible Web between 20-100 billion documents
  (Lewandowski 2006)

2012:

• 11+ billion static pages are hidden from the public as well as 450+ billion database-driven are completely invisible to Google
  (Paul Gil 2013)

2013:

• "Trillions + pages of information" that current search engines cannot find
  (Zillman 2015)
• "In fact, typical search engines like Google, Yahoo, or Bing actually access only a tiny fraction estimated at 0.03% of the internet.
  (Ultimate Guide to the Invisible Web 2013)

Updated September 2015