Independent analyses weren’t particularly kind to the American Health Care Act (AHCA), the House of Representatives’ Obamacare replacement legislation which passed last month. So far, they’re not a whole lot gentler for the Senate’s version of the legislation, which is projected to cost 22 million Americans their health insurance coverage over the next decade, according to a new Congressional Budget Office (CBO) report released Monday.

The CBO, considered the official nonpartisan scorekeeper for federal legislation, predicted that the Senate’s draft Better Care Reconciliation Act (BCRA) would lead to 15 million fewer insured people (compared to current law, as with all of CBO’s analysis) next year alone. Premiums for individual insurance health plans would also soar 20% in 2018, according to the agency.

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By 2026, 22 million fewer Americans would have health coverage and enrollment in the Medicaid safety net program for the poor “would fall by about 16 percent and an estimated 49 million people would be uninsured, compared with 28 million who would lack insurance that year under current law.” That 22 million figure is just a one-million person improvement over what the CBO predicted would happen under the deeply unpopular AHCA.

The numbers could prove a major headache for Senate Majority Leader Mitch McConnell, who’s been striving for a vote on the controversial legislation by the end of this week ahead of the July 4th Congressional recess. At least four GOP Senators–a mix of moderates and conservatives—have expressed reservations about the BCRA in its current form.

Furthermore, the CBO expects the Senate’s health bill to substantially raise Americans’ out-of-pocket medical costs by slashing Obamacare’s mandated benefits and rolling back assistance to poorer and sicker people, as well as discouraging some low-income Americans from buying insurance in the first place (the BCRA would nix Obamacare’s requirement that people carry coverage or pay a fine).

That’s despite the fact that premiums would eventually be expected to decline after 2020—in fact, it’s related. Deductibles would largely be expected to rise and many plans would cover less than 60% of average expected out-of-pocket medical costs. Those deep cuts are also why CBO projects the bill would, on net, save the federal government $321 billion over the next ten years.

These projections are preliminary and subject to change. For instance, one major factor that could influence the coverage loss (and cost hike) projections is the lack of an insurance mandate. While the Senate would be loathe to adopt an Obamacare policy it’s long slammed as government tyranny, the chamber reportedly wants to add its own version of a penalty for not carrying insurance: locking people who don’t maintain continuous health coverage out of the individual health market entirely for six months.

We’ll have deeper analysis of the Senate’s bill in the coming days.