The disappearance of Malaysia Airlines Flight MH370 in March 2014 sparked a search mission that has spanned thousands of square kilometers of seabed and absorbed millions of dollars. But the team hunting for the missing aircraft and its 239 passengers and crew has come up with few clues as to what happened.

Here are five key numbers about the search:

$130 million

The cost of covering the entire search area. In a multinational hunt led by Australian, Malaysian and Chinese authorities, the Chinese government has contributed about $14 million, including the sonar-equipped vessel Dong Hai Jiu.

101.3 million

The number of components in the missing Boeing 777. The plane was delivered new to Malaysia Airlines in May 2002, and had a maintenance check less than a month before it disappeared.

120,000 sq km

The size of the search zone in the southern Indian Ocean. The total area — the equivalent of 46,330 sq. miles (120,000 sq. km) — is about half the size of the U.K. and ships have less than 35,000 sq. km left to scour.

20 petabytes

The amount of data that ships have collated from the search zone without finding the plane, the equivalent of 20 million gigabytes. That's enough to house the entire digital collection of the U.S. Library of Congress — several times over.

1

The number of items that have been recovered from MH370 since it disappeared. The wing flap was found on Reunion Island in July, thousands of kilometers from the search area. Investigators said the location was consistent with the influence of ocean currents on any debris.