Push-ups are 64% of Your Body Weight

In a regular push-up, you lift 64 percent of body weight, whereas with a knee push-up, you lift 49 percent. If you're new to training, performing the push-up with hands elevated on a 24-inch bench will allow you to lift even less than a knee push-up, at 41 percent of body weight.

Source:
https://www.quora.com/How-much-body-weight-is-used-on-a-push-up