hi i have 2 lutron dimmer switches ,i am told about 15 years , power in 119 volt , maximum volt out 91 volt, is this standard or do they degrade . not sure of model no, they has a center on off switch with a small slider control for dimming next to on off switch.
Are you using a true rms meter?
That sounds like a more modern dimmer, as one for Dimmable Fluorescent or LED. Get the number off it and go to the Lutron site, they should be able to tell you what you have. BTW the Fluorescent/LED dimmers have an adjustment limit switch under the wall plate. The old Incandescent dimmers worked by rapidly switching the power on and off to the lamp.