Del. Code tit. 12, § 703

Where there is no sufficient evidence that 2 joint tenants or tenants by the entirety have died otherwise than simultaneously, the property so held shall be distributed one half as if 1 had survived and one half as if the other had survived. If there are more than 2 joint tenants and all of them have so died, the property thus distributed shall be in the proportion that 1 bears to the whole number of joint tenants.