Last week, another company announced it would plant a flag in downtown Detroit. Lear Corp. bought a building around the corner from the Detroit Opera House and Music Hall in the heart of what's now called Paradise Valley (formerly known as Harmonie Park).

Lear joins a list of companies with new Detroit offices -- automaker FCA in Chrysler House; the law firms Varnum and Jones Day; MarxModa, a Herman Miller dealership and consulting company; the accounting firms Plante Moran and ShindelRock; and so many more. Even a few headquarters, such as MSX International Inc., have moved to downtown.

You can feel it on the street -- in the restaurants that seem to be opening at a comfortable clip.

So what's the impact of one of these new offices on Detroit?

Leave it to an accountant to figure it out.

Earlier this year, Dianne Wells, managing partner of Plante Moran's Detroit office in the former Compuware building, asked her team to pull together the numbers showing the impact of the accounting firm's downtown office in the year after 60 employees moved there in November 2013.

"Sixty people may not sound like much," Wells said, "but we've had an impact. Every dollar we spend downtown for the office, we use local people, local vendors."

Here's what the accounting firm found when it tallied its impact from November 2013 through November 2014:

Food/hospitality: 1,200 visitors, either clients or others that the firm hosted.

Staff sponsorship and volunteer participation: A slew of events, including a charity project for Alternatives for Girls, the Inforum annual auto show breakfast and a cleanup activity on the city's North End.

Civic leadership: Board roles at everything from The Parade Co. to United Way to the Michigan Opera Theatre.

Recreation: Broomball league at Campus Martius and softball team on Belle Isle; Red Wings, Tigers and Lions games.

Purchasing: Held the firm's annual conference with more than 1,500 attendees (Fox Theatre) and 500 room nights at downtown hotels; hired Fathead to create graphics for the downtown office as well as Chicago and Flint outposts.

The second year, Plante Moran did even more. The firm's annual meeting, still at the Fox in 2015, included a night-before party for 800 in Campus Martius Park.

And Wells says the Plante Moran office will double -- to about 120 people -- by the end of this year.

So that feeling on the street? It's more than a feeling.