VCF0710 Ticket-splitting: President/Senate

QUESTION:
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Ticket splitting Presidential vs. Senatorial vote

VALID_CODES:
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1.  Dem. Pres. - Dem. Senate
2.  Dem. Pres. - Rep. Senate
3.  Rep. Pres. - Dem. Senate
4.  Rep. Pres. - Rep. Senate

MISSING_CODES:
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0.  DK/NA who voted for in presidential or congressional
    race; did not vote; refused to say if voted; DK/NA if
    voted; refused to say who voted for; "other"
    (independent/3rd party) vote; name given by R not on
    candidate list (1978-1988); Washington D.C.; no 
    Post IW; voted, but not for president (1980-1992);
    voted, but not for Senate (1978-1992); did not
    vote in regular Senate election (California, 1992
    ONLY); forms III,IV (1972); no Senate race in state
Inap. question not used

NOTES:
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Derived from VCF0704 and VCF0708.

WEIGHT:
-------
VCF0009/VCF0009a

TYPE:
-----
Numeric  Dec 0

SOURCE_VARS:
------------
1952:  520178,520186
1956:  560203,560211  
1960:  600201,600210
1964:  640286,640289  
1968:  680316,680320
1972:  720478,720482
1976:  763665,763670 
1980:  800993,800994,801001,801002 
1984:  840787,840788,840796,840798 
1988:  880763,880773  
1992:  925609,925628 
1996:  961082,961093
2000:  001249,001275
2004:  045026,045038x