A week ago, Google CEO Larry Page announced that Google+ had surpassed 10 million users. A couple days ago, Paul Allen, founder of Ancestry.com estimated the number to be nearly 18 million (he had guessed 10 million prior to Page’s announcement).

Much of the talk about Google+ is how it will stack up to Facebook in the long-term. Experian Hitwise shared some numbers for how it stacks up in the short-term. The firm has Google+ as ranked the #42 most visited social networking site in the US for the week ending July16.

“Google+ was ranked as the 638th most visited site among all sites in the US last week (July 16th), up from its previous ranking as the 2404th most visited site in the US the previous week (July 9th),” s spokesperson for Experian Hitwise tells WebProNews.

“Google+ received more than 1.8M total visits last week ending July 16, 2011. That is an increase of 283% vs. the previous week and an increase of 821% vs. the week ending July 2nd.”

56% of upstream traffic to Google+ last week came from other Google properties, the firm says. This isn’t very surprising, considering the service is available via the navigation bar across various Google services. As the company integrates it in even more ways, even more traffic will come from other Google properties (which in my opinion is a key element of what might make Google+ successful). Google.com accounted for 34% of upstream traffic to the site.

37% of Upstream traffic to Google+ last week came from search engines, while email provided the second largest amount of upstream traffic accounting for 21%. With email notifications, it makes sense that it would provide a significant amount.

“57% of visits to Google+ are from males (4 weeks ending July 16th),” Experian Hitwise said. Much of the talk has been about how males have dominated Google+, but this figure makes it seem much more balanced than previous ones.

38.37% of visits are from users age 25-34 for the 4 weeks ending July 16th, the firm says, while for the previous week, users ages 18-34 made up the majority of visits with 38.11%.

30.1% of visits are from users with a VantageScore between 800-900, the 2nd highest group.

” Most visits overall to Google+ were coming from the Los Angeles DMA followed by New York City, San Francisco for the 4 weeks ending July 16th,” said Experian Hitwise.  “Visitors from the Bowling Green, KY DMA, Portland, OR DMA and Bend, OR DMA were most likely to visit Google+ last week.”

As Google+ attracts more celebrities and businesses, more users are sure to follow.