Wouldn't this ratio be highly affected by the ratio of publicly-traded versus privately traded companies?

What does this figure tell us?

If several large companies were to IPO, then the ratio would rise rapidly, but little would have changed within those companies or the country. Similarly, if a number of large companies had management buyouts with private equity, again the ratio would drop - but those companies would continue to operate with the same staff doing the same things.

Not sure what conclusions we can draw from this data?