Washington ? After bolting out of the starting gate at the beginning of the year, the U.S. economy slowed in the spring, growing at an annual rate of just 1.1 percent.

The Commerce Department’s latest reading Thursday on gross domestic product in the April-June quarter was unchanged from its initial estimate a month ago. GDP measures the total value of goods and services produced within the United States and is considered the best barometer of the country’s economic health.

The 1.1 percent growth rate marks a slowdown from the brisk 5 percent pace posted in the first three months of the year.

Beyond that, analysts believe the economy picked up a bit in the current quarter, with some estimates ranging from growth rates of around 2 percent to 3 percent. For the second half of this year, some economists are predicting sluggish to moderate growth.

The economy’s struggles pose a challenge for President Bush and will be a key topic for voters heading into the November elections.