A study of companies with U.S. revenues greater than $8 billion from the Hildebrandt 2005 U.S. Law Department Survey indicates a correlation between company revenues and number of attorneys. The median number of U.S. attorneys per 1,000 US employees is 1.5, but, more importantly, as revenue per employee increases, so does the number of attorneys per employee.
Cause and effect may be tangled. It could be that plentiful legal support helps everyone in the company produce more; it could be that busy, well-run companies, generating more revenue per employee than the norm, drive the need for more lawyers. It could be that employee revenue and lawyers per unit of revenue have no actual correlation, but some third factor (or factors) cause them to oscillate together.