Twitter kicked off what has become semi-annual transparency report season late last week, reporting an 11% increase in requests from the U.S. government for data about its users in the first half of 2013 compared to July to December of last year. Compared to the same period a year ago, requests were up 33%.

From Jan. 1 to June 30, there were 902 requests from the U.S., making up about 78% of requests from all countries.

The number of users or accounts affected by those U.S. requests was up 15%, while the number of cases in which data was ultimately released was down slightly to 67%.

Similar transaprency reports from Google and Microsoft are expected soon. Those two and Twitter have been making regular updates on user data requests, with Google doing so the longest — and with the most detail.

The reports in recent months are of greater urgency given recent controversy over government surveillance.

Earlier this summer, a number of companies that had not traditionally been making regular releases about data requests issued reports in response to revelations that the National Security Administration was amassing enormous databases of online and phone activity. (View a table with that data here).

In the U.S., the percentage of requests that came via search warrant was up slightly while the number from subpoenas — the most common — was down by the same amount.

The U.S. accounts for about 4 out of 5 requests from around the world, although that number dropped slightly in the first half of 2013 as the number of non-US requests rose by nearly one-third.

Japan had the most requests after the U.S., but that was only 8% of total requests. In almost all cases, data is actually released to foreign countries at a much lower rate than in the U.S. The percentage for Japan, for example, was 16% compared to 67% in the U.S.

The chart below shows growth in global requests.

Read more stories on the transparency reports.