What is the evidence of the amount of litigation costs in a personal injury action?

Once again the evidence of the amount of litigation costs was insufficient. "'[T]he default of the defendant merely admits that something is due but does not admit that the amount prayed for constitutes that amount.'" (Lynch v. Bencini (1941) 17 Cal.2d 521, 526.) Code of Civil Procedure section 585, subdivision (d), permits evidence of the amount of damages to be submitted by affidavit, but "[t]he facts stated in the affidavit or affidavits shall be within the personal knowledge of the affiant and shall be set forth with particularity, and each affidavit shall show affirmatively that the affiant, if sworn as a witness, can testify competently thereto."