It's valuable to learn a lot about Medicare so that you approach it and use it with your eyes open, making smart decisions that can benefit both your health and your wallet.

Here are eight Medicare-related stats that should help you better understand the government-run healthcare program. Many or most of them will likely surprise you, too.

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Medicare is big business

The first thing to appreciate is just how big Medicare is. Consider:

$684 billion: That's how much Medicare benefit payments totaled in 2016, and they're projected to rise to $709 billion in 2017. That's more than the gross domestic product of Switzerland and close to the recent total market values of Microsoft and Coca-Cola -- combined. 

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15%: In 2015, Medicare spending made up a remarkable 15% of the federal budget. It also accounted for 20% of all health spending in America in 2014, as well as 29% of prescription drug retail sales, 26% of hospital care expenses, and 23% of physician services costs.

57,351,559: There are more than 57 million enrollees in Medicare, as of October, 2016. Considering that there are roughly 325 million people in America, that's a hefty 18% of the population -- nearly 1 in 5. Among the 57 million, more than 17 million enrollees are estimated to have signed up for Medicare Advantage plans in 2016. Medicare Advantage plans are alternatives to the "original" Part A and Part B of Medicare, offering as much coverage and often more.

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The ACA has strengthened Medicare in many ways

It's important to understand the role that the Affordable Care Act (the ACA, often referred to as Obamacare) has played in Medicare's health -- because the current administration in Washington is interested in repealing the act and replacing it with an as-yet-unspecified alternative. Here are some things to know:

4.4%: The ACA was designed, in part, to contain healthcare costs that were rising at rapid rates. Data from the Kaiser Family Foundation (KFF) shows that Medicare spending grew at an annual average of 9% between 2000 and 2010, and then slowed to an annual average of 4.4% between 2010 and 2015. And that's despite baby boomers starting to enter the Medicare rolls in 2011. The KFF also notes, "Average annual growth in spending per beneficiary averaged 1.4% between 2010 and 2015, down from 7.4% between 2000 and 2010."

$800 billion: If the ACA is repealed, our government will lose an estimated $800 billion in tax revenue, according to the not-terribly partisan Committee for a Responsible Federal Budget. It's a little more complicated than that, though: "According to our latest estimates, repealing the ACA in its entirety would cost roughly $350 billion through 2027 under conventional scoring and $150 billion using dynamic scoring." Also: "Repealing the ACA's coverage provisions would save $1.55 trillion through 2027, while repealing its tax increases would cost $800 billion, and repealing its Medicare (and related) cuts would cost another $1.10 trillion. Repeal would also lead to a small increase in economic growth, which could produce over $200 billion of additional net savings." Clearly, there are costs and savings realized via a repeal. Some of the costs are human:

23 million: If the ACA is repealed, about 23 million people will lose health insurance coverage. That will lead to tough or impossible choices for many: Risk financial disaster to pay for healthcare, or go without and risk a shorter life. While the ACA has indeed introduced some new costs to the federal budget, it has also ushered in some greater financial efficiencies while covering millions of Americans. Also, per Kaiser, "Medicare spending would rise primarily as a result of repealing the ACA's reductions to payments to providers and Medicare Advantage plans. An increase in Medicare spending would likely lead to higher premiums, deductibles, and cost sharing for beneficiaries, and would accelerate the projected insolvency date of the Medicare Hospital Insurance trust fund." 

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Using Medicare wisely can improve your physical and financial health

But let's ignore the current turmoil surrounding the ACA and just look at Medicare as it stands today -- and how you might make the most of it.

$0: That's how much you pay for an annual wellness visit with your doctor, per Medicare. It's also how much you pay when you get certain screenings, such as mammograms, colonoscopies, diabetes screenings, and many more.

5: That's how many stars are in Medicare's rating system for services and facilities such as hospitals, dialysis centers, Medicare Advantage plans, nursing homes, and more. A five-star rating is the best you can get, but as of July, when 3,617 hospitals were rated, only 102 earned all five stars. For 2017, about 49% of Medicare Advantage plans with prescription drug coverage were rated with four or five stars -- covering about 68% of enrollees. The rating system for hospitals takes into account measures such as the rate of post-surgical infections and emergency room wait times. Medicare Advantage plans are evaluated on measures such as how well they're keeping their members healthy (via screenings, checkups, and more), how well they're managing members' chronic conditions, and how good their customer service is. You'll find the star ratings of plans available to you by using the Medicare Plan Finder at the Medicare website.

The more you learn about Medicare, the better use you'll be able to make of it, such as by taking advantage of available screenings that could detect problems before they get worse. As you follow developments regarding Medicare and the ACA in the news, consider letting your representatives in Washington know what you think about them. 

Teresa Kersten is an employee of LinkedIn and is a member of The Motley Fool's Board of Directors. LinkedIn is owned by Microsoft. Selena Maranjian owns shares of Microsoft. The Motley Fool recommends Coca-Cola. The Motley Fool has a disclosure policy.