Teachers are striking all over. What is going on?

Show Caption Hide Caption Kentucky teachers protest pension bill Hundreds of Kentucky teachers called in sick on Friday to protest last-minute changes to their pension system, forcing nearly two dozen districts to close while educators rallied outside of the governor's office to demand he not sign the bill. (March 30)

Teachers across the country are striking and protesting en masse, shutting down school systems and putting the pressure on state lawmakers to meet their demands.

At least four states this year have mobilized, often with similar gripes. Educators in West Virginia and Oklahoma are lobbying for more pay while Kentucky's teachers are fighting proposed changes to their pensions plans. West Virginia teachers forced lawmakers to give them 5% raises.

Using 2016 data, the National Education Association ranked New York as the state with the highest average teacher salary, which was $79,152. South Dakota ranked last with an average salary of $42,025.

Read more: Arizona teacher posts salary: 'I need a college degree to make this'

Here's what's going on in each state:

Arizona

About 2,500 Arizona teachers rallied at the state's Capitol in Phoenix on Wednesday, demanding a 20% raise from Gov. Doug Ducey and the state Legislature.

There are now rumors the teachers could strike.

Arizona ranked 43rd in average teacher pay in 2016 at $47,218, according to the NEA.

Ducey and some Republican lawmakers didn't directly address the teachers' demands. Ducey, through spokesman Patrick Ptak, said the state has made concessions to teachers in the past, most notably a 4.3% raise from 2016 to 2017. In response, Democrats bashed the governor while highlighting how the state ranks low in teacher pay nationally.

Kentucky

Educators across Kentucky called out of work together, forcing school closures in at least 20 counties as they fight proposed changes to their pension plans.

The teachers requested substitutes or called in sick, leaving administrators unable to cover the absences.

On Thursday evening, a new Republican-backed bill passed through the state Legislature. The bill changes teachers' defined-benefit plan to a hybrid plan with features of a traditional pension plan and a 401(k)-style savings plan. It also makes restrictions on how sick leave payments affect retirement benefits.

Kentucky's average teacher salary was $52,135 in 2016, putting them at 26th in the nation.

Oklahoma

Oklahoma's teachers plan to stage a walkout Monday, CNN reports, just days after Gov. Mary Fallin approved a $6,100 average pay raise.

The raise, Time reports, amounts to a 16% bump and was paid for by raising taxes on cigarettes, fuel and lodging. Fallin called it "the largest teacher pay raise in the history of the state."

Despite the raises, the state's largest teachers union, the Oklahoma Education Association, called it "incomplete," reports CNN. The teachers plan to walk out on Monday and will hold a rally at the state's Capitol in Oklahoma City.

The state ranked 49th in average teacher salary in 2016 at $45,276, notes the NEA.

This is about so much more. Our students deserve better. We will be at the Capitol on Monday, April 2 and remain there until we get a deal for students. #oklaed #oklaedwalkout #TogetherWeAreStronger #OKwalk4kids pic.twitter.com/UoYegS6KJl — OK Education Assoc. (@okea) March 30, 2018

West Virginia

West Virginia's 20,000 teachers held a nine-day strike from late February to early March, which ended when Gov. Jim Justice signed a contract giving teachers and about 10,000 support staff a 5% raise.

Randi Weingarten, national president of the American Federation of Teachers, said West Virginia's teachers were some of the lowest paid in the United States. They had gone years without a raise while rising health-care costs cut into their income. The average teacher salary in West Virginia before the pay raise was $45,622.

Teachers rallied at the state's Capitol in Charleston throughout the strike, which resulted in suspended classes for some 275,000 public school students.

Contributing to this story: John Bacon and Greg Toppo of USA TODAY; Dustin Gardiner, Kaila White, Lily Altavena, Andrew Nicla and BrieAnna J. Frank of the Arizona Republic;