Teachers have no idea how much money their local school districts spend per student, they just want more spending.

Teachers surveyed in the 2015 Education Next poll estimated that their local school district spends a little more than $7,000 per student. The actual amount? $12,325. The teachers were off by 72 percent. That's certainly worthy of a failing grade on this test.

Following that question, teachers were asked to estimate average per pupil spending across the country. Their estimates dropped slightly, down to $6,783. The actual amount: $12,010. Wrong by 77 percent.

Next, teachers were asked if funding in their district should go up or down. Some were told how much money is actually spent per student in their school, others were not. Either way, teachers wanted more spending in their schools. Despite massively underestimating how much money is spent in schools, teachers asked for more.

In other words, it doesn't seem to matter to teachers how much is spent in schools. They just know they want more.

To be fair, all of the groups in the survey grossly underestimated the actual levels of spending in their local schools and across the country. Those groups include parents, racial minorities, and both major political parties.

But teachers are in schools almost everyday and have the most contact with the administrators who set school budgets. Teachers are also the ones in the powerful unions that many politicians bend over backwards to please.

With all that power and ease of access to information, you'd think teachers would have a better idea of how much their school spends.

It's also possible that the gap shows the difference between how much is spent on education and how much reaches the classroom. There's a difference between spending on instruction and spending that gets swallowed up in bureaucracy or non-instructional services.

The poll also included results from questions about how much different levels of government spend on education. The federal government spends only 10 percent of all funding for schools, with state and local governments equally splitting the remaining 90 percent. Teachers massively overestimated the role of the federal government in education, guessing it spent 30 percent of all school funding. Even so, teachers called for the federal government to take on an even bigger role in education, saying they desired the federal government to provide 35 percent of all funding.

The poll had a total sample size of 4,083, including a nationally representative cross-section of teachers. Results were released Tuesday.