It's been a whole year since Microsoft released its first truly competent antivirus, and the company is celebrating its anniversary by sharing a number of user statistics and other noteworthy highlights. Since its 2009 debut, Microsoft Security Essentials has been installed on 31 million computers – 27 million of which reported infections to the Microsoft Malware Protection Center (MMPC).

MSE's largest install base is in the US, while Brazil, Japan, the UK, Germany, France, Canada, China, Italy, the Netherlands, and Russia fill out the top ten non-US regions using the antivirus, which is available in 27 languages and 74 countries. "Language shouldn't be a barrier to good security. Money is no problem, either – Microsoft Security Essentials is available at no cost," Microsoft said.

Over two million machines were attacked in the US over the last year, while China (eighth largest user base) reported 693,347 infections. Brazil followed with 586,888 attacks, the UK saw 212,875, and the rest reported well under 200,000. In all, 400 million threats were reported and customers removed 366 million of them. Microsoft dissects the threat families in the chart at the bottom of this page.

Microsoft recently opened its arms to small business users. Starting next month, office settings of up to 10 computers will be allowed run MSE free of charge. Also, HP will be shipping MSE preinstalled on its new Envy 14 notebook series (which we're in the middle of reviewing, by the way). The next version of Microsoft Security Essentials is currently in beta and it should arrive sometime early next year.