WASHINGTON -- Troops would get their biggest pay raise in years under the final version of Congress' annual defense policy bill unveiled Tuesday.

The 2.1 percent increase included in the National Defense Authorization Act would break a five-year trend of raises that have fallen below the private sector. The higher pay would go into effect Jan. 1 if the bill is passed by Congress, and it could receive an initial vote in the House on Friday.

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The massive $618.7 billion policy bill also includes $3.2 billion to boost troop numbers and bolster Marine Corps and Air Force aviation, a military health care overhaul and a requirement to study whether women should be included in the military draft.

The NDAA was hashed out during months of negotiations between the House and Senate, which had disagreed about an $18 billion spending hike for the military. The proposal was pared down in the final bill, but the $3.2 billion increase could run into opposition from Democrats, who have demanded any additional defense spending be matched with dollars for domestic programs.

Military pay raises have been kept below 2 percent since 2011. Meanwhile, troops and families have been stressed by deployments, aging equipment and shrinking overall defense spending.

The National Military Family Association has said troops are being "nickel-and-dimed" and that a higher pay raise is among its top priorities.

The language in the NDAA overrides President Barack Obama's order to set pay raises at 1.6 percent in 2017, which was a slight increase over the president's decision to keep raises at 1.3 percent this year.

The bill also freezes a drawdown in the Army, keeping its end strength at 476,000, and boosts Reserve forces by 4,000. The Marine Corps would get 3,000 more troops, according to a briefing on the bill by senior aides with the House Armed Services Committee.

The House aides said the additional $3.2 billion will also help fill gaps in military readiness especially for the Air Force and Marine Corps, which have maintenance and training problems with F-18 fighter jets and CH-53 helicopters.

Tricare, the military's health care program, would be overhauled to shore up its financial future and expand some access to health care facilities, according to the House briefing.

"We do raise the co-pays and fees on the next generation of military," a senior aide said.

Active-duty troops and current retirees would not be affected by the fee increases. But service members who join the military beginning in 2017 will face higher costs for themselves and their beneficiaries when they retire.

The House and Senate conference committee rejected a proposal to require women between 18-25 years old to register with the Selective Service, as men are now required to do. The Selective Service could be used if the United States reinstitutes the military draft, which for now remains an unlikely scenario.

The proposal raised the ire of some conservative lawmakers, and the NDAA instead calls for a study of the issue, which was a proposal favored by the House.