SEATTLE (AP) — The union representing striking Boeing factory workers says members will vote Monday on a new contract offer from the company that provides slightly bigger wage increases than an offer that was rejected last week.

Boeing 's latest offer would raise wages 38% over four years, or a compounded increase of about 43%, the International Association of Machinists and Aerospace Workers said Thursday.

Boeing in a statement Thursday said the company was also offering a $12,000 contract ratification bonus, up from $7,000 offered previously. Additionally, the company said it would increase its contribution to employee 401(k) plans.

About 33,000 IAM members have been on strike for seven weeks, shutting down production of most Boeing airline jets including the company's best-seller, the 737 Max.

The strike began Sept. 13 when more than 94% of workers voting rejected an offer of 25% over four years. Last week, 64% shot down a proposal that would have raised general wages 35% over four years.

The union originally demanded 40% in raises over three years and restoration of traditional pensions, which were frozen for then-current workers and not extended to those hired after January 2014. Workers on picked lines in the Seattle area have stressed pensions, but the company based in Arlington, Virginia, is unwilling to bend on the issue.

Boeing has said that average annual pay for machinists is currently $75,608.

The last Boeing strike, in 2008, lasted eight weeks and cost the company about $100 million daily in deferred revenue. A 1995 strike lasted 10 weeks.