Charles E. Grassley won with 68.4% of the vote (648,480 votes), ahead of David Osterberg with 30.5% (289,049 votes).
The margin between the first two candidates was 37.9 percentage points (359,431 votes). The party margin (Republican share minus Democratic share) was a Republican lead of 37.9 points.
Compared with the previous comparable race in the same area, the party margin moved 43.0 points toward Republicans. The winning party changed.
947,907 votes were counted in this race, for 5 candidates or options.
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