how many broadcasters performed at least twice?
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col : season | network | play-by-play | color commentator(s) | sideline reporter(s) row 1 : 1969 | cbs | jack whitaker | frank gifford and don perkins |  row 2 : 1968 | cbs | ray scott | paul christman | frank glieber row 3 : 1967 | cbs | frank glieber | frank gifford |  row 4 : 1966 | cbs | chuck thompson | tom brookshier |  row 5 : 1965 | cbs | frank glieber (first half) and chuck thompson (second half) | pat summerall |  row 6 : 1964 | cbs | jack drees (first half) and earl gillespie ( | frank gifford |  row 7 : 1963 | cbs | ray scott (first half) and ken coleman (second half) | frank gifford |  row 8 : 1962 | cbs | chris schenkel (first half) and ray scott (second half) | warren lahr |  row 9 : 1961 | cbs | chris schenkel (first half) and van patrick (second half) | johnny lujack |
how many broadcasters performed at least twice?
Season Network Play-by-play Color commentator(s) Sideline reporter(s)
1969 CBS Jack Whitaker Frank Gifford and Don Perkins
1968 CBS Ray Scott Paul Christman Frank Glieber
1967 CBS Frank Glieber Frank Gifford
1966 CBS Chuck Thompson Tom Brookshier
1965 CBS Frank Glieber (first half) and Chuck Thompson (second half) Pat Summerall
1964 CBS Jack Drees (first half) and Earl Gillespie (second half) Frank Gifford
1963 CBS Ray Scott (first half) and Ken Coleman (second half) Frank Gifford
1962 CBS Chris Schenkel (first half) and Ray Scott (second half) Warren Lahr
1961 CBS Chris Schenkel (first half) and Van Patrick (second half) Johnny Lujack
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