The 2014 elections are projected to be the most expensive midterms to date. Each election cycle, the cost of elections increases substantially. In 1998, candidates, parties and outside groups spent $1.6 billion total on Congressional races. By 2012, that figure more than doubled to $3.7 billion and is expected to rise again in 2014.
Counterintuitively, while election spending increases each cycle, there are fewer swing seats and competitive races taking place. According to the Cook Political Report Partisan Voter Index, there were 164 swing seats in the House in 1998. By 2013, that had dropped to 90. Even fewer, maybe 20-30, are actually competitive.