Overall, firms promote 8.9 percent of employees, while new hires make up a much larger portion of positions being filled, at 30.2 percent. However, for management positions, firms promote more internally than they hire externally — 17.2 percent of managers are promoted, while 15.6 percent are new hires. For the C-Suite and other top positions, 21.5 percent are internally promoted and only 12.5 percent are new hires.

“Employers can compare their rate of internal promotion against national and industry benchmarks to determine the health of career development programs, learning and development and the cost of losing high potential front-line workers,” the authors write. “In addition, externally hired managers are more likely to increase total compensation costs.”

The report also found that employee turnover varies significantly with demographic factors. Not surprisingly, monthly turnover rates for older employees are relatively lower compared to workers in younger age groups: the overall turnover rate for those 65 and older is 2.2 percent, while turnover successively increases across younger age groups to 8 percent for those age 25 years or less.

What may be surprising is that turnover rates are very similar across genders, with males leaving their jobs at a rate of 3 percent per month and females at 3.5 percent per month overall.

“Employers can compare employee turnover against national and industry benchmarks split out by age and gender to pinpoint organizational issues,” the authors write.

Another key finding: on average is takes 6.6 years for women to be promoted to their first management promotion, while on average it take 7.3 years for men. However, as women move up management levels, there is a steep decline at the third level of management, with women hitting the proverbial “glass ceiling” at the fourth level.

“While less than half of one percent of all American workers reach the three highest management tiers, the under-representation of women is problematic because these elite positions have an outsized influence on corporate policy and culture,” the authors write.

“The average wages of job holders in these fourth-level management positions is also 40 to 50 percent higher,” they write. “Considering that these leadership positions typically require candidates with substantial job tenure and mentoring, short-term fixes will be challenging.”

Read more: 

• IBM can predict when employees are planning to quit
• More professionals prefer promotions to raises
• How the right employee benefits can drive employee retention