To assess which Minnesota House races are competitive follow the money.

Democratic and Republican groups have spent more than $100,000 on at least 20 seats, almost all held by Democrats.

The DFL is on defense, desperately holding on to its majority in the 134-member House. Republicans are just as anxious to snatch that control away in this off-year election.

Explore the spending on the key races to decide the majority below.

All told, as of Oct. 20, the House candidates and outside groups, including parties and political action committees, have spent more than $13 million on the contest for the lower chamber.

Click on each bar to see the exact amount of money spent.

These figures only include spending by groups registered with the Minnesota Campaign Finance and Public Disclosure Board, as of Oct. 20. They do not include the significant cash spent by political nonprofits, whose spending largely is unreported before elections. Republican-supporting groups have spent considerable sums through political nonprofit organizations.

Here are the candidates competing in those 20 races:

UPDATE: Most of the money spent on 48B was spent during the contested August primary.

Glenn Howatt contributed to this post.