Statistics PhD - Sending the math GRE score
It really depends. Obviously if the score is required you need to send it. If you are applying to top programs, a 68% at anything is not going to help your case so I would not send it if it wasn't required. At lower ranked schools, a 68% might be okay, but again it is probably not going to impress anyone. I would probably draw the line at the 90th percentile for providing something that is not required.