When it comes to diversity, more companies want their law firms to show, not just tell.

The number of corporate legal departments demanding detailed data on the diversity of their outside legal teams is taking off, according to Tom Bender, co-president and co-managing director of 1,300-lawyer Littler Mendelson.

In 2016, seven clients asked for the labor and employment firm's overall demographic data and for specific diversity information about the lawyers assigned to work on their matters, Bender said.