It's no secret that U.S. students are horrible at geography and have been for some time.

Nearly three-quarters of eighth-graders tested below proficient in geography on the 2014 National Assessment of Educational Progress – also known as the Nation's Report Card – and that's almost exactly the same result as in 1994.

U.S. Government Accountability Office.

It's a similar case when looking at prior NAEP assessments of fourth- and 12th-graders, approximately 80 percent of whom tested below proficient in 2010.

But now there's a better understanding for why that might be.

A new report from the Government Accountability Office found that more than half of social studies teachers spend 10 percent or less of their time on geography. Social studies is the umbrella subject under which geography is taught, along with things like history, civics and economics.

What's more, a majority of states do not require geography courses in middle school or high school. As of 2013, only 17 states required a geography course in middle school and 10 states required a geography course for students to graduate from high school.

"A key challenge to providing geography education is the increased focus on other subjects," said Jacqueline Nowicki, the GAO's director for education, workforce and income security issues and the lead author of the report.

State education officials and K-12 teachers interviewed as part of the investigation told the GAO researchers that spending time and resources on geography education is difficult due to the heavy emphasis placed at both the national and state levels on reading, math, and science. Federal law, for example, requires students to be tested in all three areas.

"One state official told us how the state had eliminated geography from the curriculum for over a decade, and only recently added geography courses back amid concerns from the community that students were lacking essential geography skills," Nowicki said.

The growing use of geographic information and location-based technology across multiple sectors of the economy, the GAO researchers explained, has prompted questions about whether K-12 students have the adequate skills and exposure to geography they'll need to fill workforce needs later in life.

Those concerns are valid: According to the Department of Labor, the employment of geography specialists is projected to grow 29 percent from 2012 to 2022 – much faster than the average 11 percent growth for all occupations.

Some of those positions require skills and knowledge in areas like maintaining roads and other types of transportation infrastructure; quickly responding to natural disasters like floods, hurricanes, and fires; and tracking endangered species.

The report noted that many geography teachers do not have an educational background in the subject and took few, if any, geography courses in college.

The GAO researchers also identified other challenges to educators being able to adequately teach geography and students being able to grasp it, including a lack of teacher preparation and professional development in the subject, poor quality of geography instructional materials, and limited use of geographic technology in the classroom.

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Half of teachers interviewed for the report described difficulties accessing resources for geography education – meaning everything from getting quality classroom materials to being able to take field trips. Seventy percent reported frustrations – such as outdated software, lack of technical support at their school and poor Internet connections – with using technology to teach the subject.

Strapped for federal dollars as it is, the U.S. Department of Education has a limited role in geography achievement rates. It's behind the NAEP exam, but even that doesn't annually test students on the subject. Since 1994, the geography NAEP has been administered just four times. Officials expect to administer it next in 2018.