Tom Burt, corporate vice-president, Customer Security and Trust, said in a blog post on Wednesday that 84% of these customers were businesses and the remainder were individuals whose email was targeted.
He said most of these attacks originated from three countries: Russia, Iran and North Korea. He did not mention China which is generally the default choice when US officials ladle out the blame for cyber attacks.
Last year, Microsoft launched a security offering known as AccountGuard, which works with Office 365, a paid service. It was described at the time as "a security service designed to provide additional critical cyber protection to customers operating in the political sphere. It forms a key plank in our Defending Democracy initiative".
"While this service is relatively new, we’ve already made 781 notifications of nation-state attacks targeting organisations participating in AccountGuard," he wrote.
"This data shows that democracy-focused organisations in the US should be particularly concerned as 95% of these attacks have targeted US-based organisations. By nature, these organisations are critical to society, but have fewer resources to protect against cyber attacks than large enterprises."
The ElectionGuard solution has been designed for people to vote on the screen of a Microsoft Surface devices or using the Xbox Adaptive Controller.
"People using the demo will be provided with a tracking code that, when voting is complete, they will be able to enter into a website to confirm their vote was counted and not altered; the website will not display their actual votes," Burt wrote.
"The demo will show how ElectionGuard can enable end-to-end verifiable elections for the first time while retaining the familiarity and certainty of paper ballots."
He said ElectionGuard was available as an open-source offering on the Microsoft-owned GitHub code repository.