~10 billion formal meetings conducted a year (US)

I read an interesting research paper on Meeting Analysis earlier this week and there was one organizational metric which caught my eye – amount of formal meetings per year.
In 1988, United States Fortune 500 companies are estimated to have held between “eleven and fifteen million” formal meetings daily and between “three and four billion“ meetings yearly [13, 52].
If we want to extrapolate this number into an amount of formal meetings conducted in the US per year in 2013, we could make a few conservative assumptions; a) the 1988 fortune 500 workforce is loosely one fifth of the total 2013 workforce as per the Bureau of Labor Statistics b) the workers outside of the fortune 500 conduct only half the amount of meetings and c) the growth in formal meetings conducted between 1988 to 2013 (25 years) was 0% a year.
This set of assumptions brings us to ~10 billion formal meetings conducted in the US every year.
A more recent commentary to this number came out of The Ayers Group and their “Meetings: Time Wasted or Well Spent?” press release. They suggest that “Some 25 million meetings take place in corporate America daily”. Which again brings us close to that ~10 billion formal meetings conducted a year in the US.
Imagine 10,000,000,000 invites and the amount of time spent setting them up – and subsequently time spent participating in them. Hundreds of billions of dollars, in the US alone, in workforce productivity is being invested into the idea of a valuable meeting. I did 1019 meetings myself in 2012.