The Google Transparency Report was first released last year to highlight transparency in Google’s interaction with the common user. Google says –

Transparency is a core value at Google. As a company we feel it is our responsibility to ensure that we maximize transparency around the flow of information related to our tools and services. We believe that more information means more choice, more freedom and ultimately more power for the individual.

We've created Government Requests to show the number of government inquiries for information about users and requests to remove content from our services. We hope this step toward greater transparency will help in ongoing discussions about the appropriate scope and authority of government requests.

Our interactive Traffic graphs provide information about traffic to Google services around the world. Each graph shows historic traffic patterns for a geographic region and service. By illustrating outages, this tool visualizes disruptions in the free flow of information, whether it's a government blocking information or a cable being cut. We hope this raw data will help facilitate studies about service outages and disruptions.
- Google

The new updated data shows that the US government made requests for data of 11,057 users in the first half of 2011. Google’s compliance rate with these requests is 93%. The next highest user data requests came from India, covering a total number of 2,493 accounts, of which only 70% were complied with.

Besides the above, SearchEngineWatch have found the following facts in the report –

1. In the U.S., officials requested that YouTube videos of police brutality and content that allegedly defamed law enforcement officials be removed. Google did not comply with these requests.

2. Brazil made the most content removal requests. As noted by The Next Web, this is likely due to the popularity of the Orkut social network.

3. China made only three requests, total. Each requested the removal of large amounts of data. However, Google only complied with two of the requests, and cited AdWords violations as the reason for removal in both cases. No user data was requested, as Google doesn't keep such data in the country anymore.

4. Several regions, including India, made requests for the removal of material that violated local laws. Google generally gave partial compliance by blocking the content for the region without removing it from the core index.

5. The number of content removal and user account requests varied wildly in countries across the world. The fewest requests came from Hungary (0 requests of either type). From there, we range from the Switzerland-level (Switzerland had fewer than 10 content removal requests and just 36 user data requests) all the way up to the U.S. (11,000+ user data requests and 92 removal requests that targeted 757 total items.)

- SearchEngineWatch dotcom

I would agree with the 2nd point most, But it would be india after brazil if you talk about the popularity of orkut.