The Air Force investigation of UFO's began in 1948 and was known as Project Sign. Later the name was changed to Project Grudge, and in 1953, it became Project Blue Book. Between 1948 and 1969 we investigated 12,618 reported sightings.
The following is a statistical listing of reported UFO sightings during the Air Force investigation:
YEAR | TOTAL SIGHTINGS | UNIDENTIFIED |
1947 | 122 | 12 |
1948 | 156 | 7 |
1949 | 186 | 22 |
1950 | 210 | 27 |
1951 | 169 | 22 |
1952 | 1,501 | 303 |
1953 | 509 | 42 |
1954 | 487 | 46 |
1955 | 545 | 24 |
1956 | 670 | 14 |
1957 | 1,006 | 14 |
1958 | 627 | 10 |
1959 | 390 | 12 |
1960 | 557 | 14 |
1961 | 591 | 13 |
1962 | 474 | 15 |
1963 | 399 | 14 |
1964 | 562 | 19 |
1965 | 887 | 16 |
1966 | 1,112 | 32 |
1967 | 937 | 19 |
1968 | 375 | 3 |
1969 | 146 | 1 |
____ | ______ | _____ |
TOTAL | 12,618 | 701 |
 : Of these total sightings, 11,917 were found to have been caused by material objects (such as balloons, satallites, and aircraft), immaterial objects (such as lightning, reflections, and other natural phenomena), astronomical objects (such as stars, planets, the sun and the moon), weather conditions and hoaxes. As indicated only 701 reported sightings remain unexplained.
Attachment 2, pg 1
 : On December 17, 1969 the Secretary of the Air Force announced the termination of Project Blue Book.
 : The decision to discontinue UFO investigations was based on an evaluation of a report prepared by the University of Colorado entitled, "Scientific Study of Unidentified Flying Objects;" a review of the University of Colorado's report by the National Academy of Sciences; past UFO studies: ad Air Force experience investigating UFO reports for two decades.
 : As a result of these investigations and studies, and experience gained from investigating UFO reports since 1948, the concludions of Project Blue Book were: (1) no UFO reported, investigated, and evaluated bt the Air Force has ever given any indication of threat to our national security; (2) there has been no evidence submitted to or discovered by the Air Force that sightings catagorized as "unifentified" represent technological developments or principales beyond the range of present day scientific knowledge; and (3) there has been no evidence indicating that sightings catagorized as "unidentified" are extraterrestrial vehicles.
 : With the termination of Project Blue Book, the Air Force regulation establishing and controlling the program for investigating and analyzing UFOs was rescinded. All documentation regarding the former Blue Book investigation was permanently transferred to the Modern Military Branch, National Archives and Records Service, 8th and Pennsylvania Avenue, Washington, D.C. 20408, and is available for public review and analysis.
 : In 1977, President Carter asked the National Aeronautics and Space Adminitration (NASA) to look into the possibility of resuming UFO investigations. After studying all the facts available, they decided that nothing would be gained by further investigation. The Air Force agrees with that decision. If, however, firm evidence is found justifying further investigation, and appropriate agency will be directed to undertake the effort.
 : There are a number of universities and professional scientific organizations such as the American Association for the Advancement of Science, which have considered UFO phenomena during periodic meetings and sminars. In addition, a list of private organizations interested in aerial phenomena may be found in Gale's Encyclopedia of Associations (Edition 8, Vol I, pp. 432-3). Such timely review of the situation by provate groups insures that sound evidence will not be overlooked by the scientific community.
 : For Further reference material, two documents are available from the National Technical Information Service, U.S. Department of Commerce, Springfield, VA 22151:
Attachment 2, pg 2
 : Scientific Study of Unidentified Flying Objects. Study conducted by the University of Colorado under contract F44620-76-C-0035. Three volumes, 1,465 p. 68 plates. Photoduplicated hard copies of the official report may be ordered for $6 per volume, $18 the set of three, as AD 680:975, AD 680:976, and AD 680:977.
 : Review of University of Colorado Report on Unidentified Flying Objects. Review of report by a panel of the National Acedemy of Sciences. National Academy of Sciences, 1969, 6p. Photoduplicated hard copies may be ordered for $3 as AD 688:541.
Attachment 2, pg 2