<Table> <Tr> <Th_colspan="2"> Wheel of Fortune </Th> </Tr> <Tr> <Td_colspan="2"> </Td> </Tr> <Tr> <Th> Genre </Th> <Td> Game show </Td> </Tr> <Tr> <Th> Created by </Th> <Td> Merv Griffin </Td> </Tr> <Tr> <Th> Directed by </Th> <Td> Jeff Goldstein (1975--78) Dick Carson (1978--99) Mark Corwin (1999--2013) Bob Cisneros (2013--15) Robert Ennis (2015--present) </Td> </Tr> <Tr> <Th> Presented by </Th> <Td> Network Host Chuck Woolery (1975--81) Pat Sajak (1981--89) Rolf Benirschke (1989) Bob Goen (1989--91) Hostess Susan Stafford (1975--82) Vanna White (1982--91) Syndication Host Pat Sajak Hostess Vanna White </Td> </Tr> <Tr> <Th> Narrated by </Th> <Td> Charlie O'Donnell (1975--80, 1989--2010) Jack Clark (1980--88) M.G. Kelly (1988--89) Jim Thornton (2011--present) </Td> </Tr> <Tr> <Th> Theme music composer </Th> <Td> Alan Thicke (1975--83) Merv Griffin (1983--97) Steve Kaplan (1997--2006) Frankie Blue (2006--16) John Hoke (2007--present) </Td> </Tr> <Tr> <Th> Country of origin </Th> <Td> United States </Td> </Tr> <Tr> <Th> Original language (s) </Th> <Td> English </Td> </Tr> <Tr> <Th> No. of episodes </Th> <Td> Syndicated version: 6,000 (as of April 11, 2014) </Td> </Tr> <Tr> <Th_colspan="2"> Production </Th> </Tr> <Tr> <Th> Executive producer (s) </Th> <Td> Merv Griffin (1975--2000) Harry Friedman (1999--present) </Td> </Tr> <Tr> <Th> Producer (s) </Th> <Td> John Rhinehart (1975--76) Nancy Jones (1976--95) Harry Friedman (1995--99) Karen Griffith (1997--present) Steve Schwartz (1997--present) </Td> </Tr> <Tr> <Th> Location (s) </Th> <Td> NBC Studios (Burbank) (1975--89) CBS Television City (1989--95) Sony Pictures Studios, Culver City, California (1995--present) </Td> </Tr> <Tr> <Th> Running time </Th> <Td> approx. 22 minutes </Td> </Tr> <Tr> <Th> Production company (s) </Th> <Td> Merv Griffin Productions (1975--84) Merv Griffin Enterprises (1984--94) Columbia TriStar Television (1994--2002) Sony Pictures Television (2002--present) Califon Productions, Inc . </Td> </Tr> <Tr> <Th> Distributor </Th> <Td> King World Productions (1983--2007) CBS Television Distribution (2007--present) </Td> </Tr> <Tr> <Th_colspan="2"> Release </Th> </Tr> <Tr> <Th> Original network </Th> <Td> Daytime: NBC (1975--89, 1991) CBS (1989--91) Evening: Syndicated (1983--present) </Td> </Tr> <Tr> <Th> Picture format </Th> <Td> 480i (SDTV) (1975--2006) 1080i (HDTV; downgraded to 720p locally in some markets) (2006--present) </Td> </Tr> <Tr> <Th> Audio format </Th> <Td> Stereo </Td> </Tr> <Tr> <Th> Original release </Th> <Td> Network January 6, 1975 (1975 - 01 - 06)--June 30, 1989 (1989 - 06 - 30) (NBC) July 17, 1989 (1989 - 07 - 17)--January 11, 1991 (1991 - 01 - 11) (CBS) January 14, 1991 (1991 - 01 - 14)--September 20, 1991 (1991 - 09 - 20) (NBC) Syndication September 19, 1983 (1983 - 09 - 19)--present </Td> </Tr> <Tr> <Th_colspan="2"> Chronology </Th> </Tr> <Tr> <Th> Related shows </Th> <Td> Wheel 2000 </Td> </Tr> <Tr> <Th_colspan="2"> External links </Th> </Tr> <Tr> <Td_colspan="2"> Website </Td> </Tr> </Table> <Tr> <Th_colspan="2"> Wheel of Fortune </Th> </Tr>

How many years has the wheel of fortune been on the air
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