Autopopulate Value from Account Record

Our company creates Client Visit Reports on a regular basis using SF. We also maintain a savings percentage specific to the client on the Account record. We update the savings percentage about once a month with a new value. When a user creates a new Client Visit Report and selects the related account I would like the savings percentage to automatically populate to the Client Visit Report (which is a custom object). Once populated I would like the savings percentage value to remain constant in the custom object even thought original value on the Account record might change. Is this possible in EE?