Speaking at the Web 2.0 Summit in San Francisco, Microsoft Chief Executive Steve Ballmer says that the company plans to acquire about 20 companies a year for the next five years, with deal sizes ranging from $50 million to $1 billion, according to VentureBeat.

"We will buy smaller companies. We will buy smaller companies that make some use of open source software," said Ballmer, according to a report from CNet News. "We don't want to discourage people who would talk with us just because they do some open source."

P-I reporter Todd Bishop noted in August that Microsoft's spending on acquisitions doubled in the last fiscal year to $1.34 billion. (That doesn't include the $6 billion purchase of aQuantive, which had not closed at the time.)

Ballmer's comments today are potentially good news for Seattle area entrepreneurs and venture capitalists, since Microsoft has shown a willingness to buy companies in its backyard. (aQuantive, SeaDragon and Visio.)

More from Todd's chart:

Source: SEC filings, company presentations