(NewsNation) — Sheila Freund goes to a lot of stores — about 10 per day for the past 20 years. But she isn’t there to shop. She collects data that helps inform financial policy decisions across the world.

Freund is one of more than 400 economic assistants for the Bureau of Labor Statistics, whose work determines the Consumer Price Index, or CPI — the most common measure of inflation.

The CPI does more than track the rise of potato prices in the past year. It’s a key metric that is used to calculate federal tax brackets, cost-of-living increases, the price of school lunches and even your salary.

As Freund hit the aisles Wednesday, NewsNation tagged along to capture the perspective of one person whose work impacts pretty much everyone in the country.

Her job is straightforward: Record the prices of everyday items at stores, big and small, across the Chicago area and track how those prices change from one month to the next.

“I price a variety of items, whether they’re grocery items or household items or apparel items,” the price-tracking veteran said.

Each month, the government tracks prices for nearly 100,000 goods and services, and almost two-thirds of those price checks are done in person by CPI data collectors like Freund who visit brick-and-mortar stores. The rest of the data is collected by telephone or online.

That data is then used to determine the average change in price for a set bundle of goods and services, which is the key marker of inflation.

So when you hear phrases such as “inflation jumped 8.6% from the year prior,” it’s because of data collected by Freund and her co-workers. The federal agency has tracked the Consumer Price Index for more than 100 years, which is how we know inflation is currently at a 40-year high.

The impact of the CPI is far-reaching.

This year, Social Security payments for approximately 70 million Americans increased by 5.9% — the biggest jump in 40 years. That calculation was determined using CPI data.

So how does the BLS decide which prices to track?

The agency uses data from consumer spending surveys collected by the Census Bureau to determine which prices to follow based on Americans’ buying habits. If people are no longer buying an item being tracked in the index, it gets rotated out.

Some of the items whose average price the agency has stopped tracking over the years include salted soda crackers, beef liver, radishes, applesauce and canned peaches.

Although prices have soared across a number of industries over the last year, consumers have been hit especially hard at the grocery store, where costs are up 11.9%, and at the pump with record-high gas prices.

According to a recent NewsNation poll, 72% of people think inflation is a bigger problem than unemployment, crime or COVID-19 in the U.S. today.

When inflation finally does subside, Freund and her co-workers will be the reason you know about it.

“It’s very fulfilling to know I’m a small part of providing data to the government that’s used for important policymaking decisions,” she said.