Incumbency Advantage in Senate
 
Seeking 
No 
Defe
 ated
Percent
 
reelection
opponent
Primary
General
Reelected
1946
30
1
6
7
56.7%
1948
25
5
2
8
60.0%
1950
32
3
5
5
68.8%
1952
31
3
2
9
64.5%
1954
32
6
2
6
75.0%
1956
29
5
0
4
86.2%
1958
28
1
0
10
64.3%
1960
29
3
0
1
96.6%
1962
35
1
1
5
82.9%
1964
33
1
1
4
84.8%
1966
32
3
3
1
87.5%
1968
28
2
4
4
71.4%
1970
31
0
1
6
77.4%
1972
27
0
2
5
74.1%
1974
27
2
2
2
85.2%
1976
25
2
0
9
64.0%
1978
25
1
3
7
60.0%
1980
29
1
4
9
55.2%
1982
30
0
0
2
93.3% 
1984
29
1
0
3
89.7%
1986
28
0
0
6
75.0%
1988
27
0
0
4
85.2% 
1990
32
2
0
1
96.8% 
1992
28
0
1
3
85.7% 
1994
26
0
0
2
92.3% 
50 year Avg.
29.1
1.4
1.6
4.9
77.3%