Facebook hit 687 million users worldwide at the start of June, increasing its total monthly audience by 1.7%, according to a new study by research and marketing group Inside Facebook.

CheckFacebook.com says that Australia currently has 10,368,720 Facebook users, comprising 1.52% of the global audience. Inside Facebook said last month that Australia has 10.0 million Facebook users at the start of May, up 8.0% from 12 months before. With a population of more than 22.6 million, Australia is the 17th country with most users of the social network site, according to Inside Facebook's tally last month. Facebook is the country's most popular social networking site, followed by Twitter and LinkedIn, respectively.

According to statistics from Inside Facebook Gold analytics service -- which gets its information from Facebook's advertising tool -- Facebook is still growing towards 700 million users as the site got a boost from all regional markets outside North America.

Inside Facebook relates that the social media giant gained 11.8 million more users over May, following 13.9 million over April. In contrast, it grew by at least 20 million new users over the typical month in the past 12. Most of the new users continue to come from countries that are relatively late in adopting Facebook, as has been the trend for the past year.

The Inside Facebook study says the United States lost nearly 6 million users, falling from 155.2 million at the start of May to 149.4 million at the end of it. Its neighbor, Canada, also fell significantly, by 1.52 million down to 16.6 million. Meanwhile, the United Kingdom, Norway and Russia all posted losses of more than 100,000.

This is the first time the U.S. has lost users in the past year.

Having reached around half the total populations in Europe and North America, the site founded by Mark Zuckerberg had slower growth in these regions, Inside Facebook states. However, it noted that Palo Alto, California-based Facebook continues to rise rapidly in developing countries. For the past 12 months, Facebook made its biggest gains in Latin America, specifically Mexico and Brazil, as well as Asian nations, like India, Indonesia and the Philippines.

Vincenzo Cosenza's "World Map of Social Networks," which charts popular social networks by country, shows that Facebook is now the most popular social network in 119 out of 134 countries. Since the last map was created in December, Facebook has conquered Iran and Syria, despite censorship issues. Consenza expects the Netherlands and Brazil will be the next countries to surrender to the Facebook domination. According to data from the Facebook Ads Platform, Europe has now become the largest continent of Facebook users with 205 million users.

Facebook is expected to continue its meteoric rise once it breaks into China. Facebook is currently blocked in China because the site doesn't adhere to Chinese Communist Party rules for censoring content.

"But how much further can it go if it is to reach its goal of 1 billion monthly active users," Eric Eldon of Inside Facebook asked in his write-up of the study. "At least without getting into China -- a move that as we and many others have noted, could both give it access to hundreds of millions of users and compromise its reputation in the U.S. and many other countries around the world."