Section 5001. Interest to verdict, report or decision

(a) Actions in which
  recoverable. Interest shall be recovered upon a sum awarded because of a
  breach of performance of a contract, or because of an  act  or  omission
  depriving  or  otherwise  interfering  with  title  to, or possession or
  enjoyment of, property, except that in an action of an equitable nature,
  interest and the rate and date from which it shall be computed shall  be
  in the court's discretion.
    (b)  Date  from  which  computed.  Interest shall be computed from the
  earliest ascertainable date the cause of  action  existed,  except  that
  interest  upon  damages  incurred  thereafter shall be computed from the
  date incurred. Where  such  damages  were  incurred  at  various  times,
  interest  shall be computed upon each item from the date it was incurred
  or upon all of the damages from a single reasonable intermediate date.
    (c) Specifying date; computing interest. The date from which  interest
  is to be computed shall be specified in the verdict, report or decision.
  If  a  jury  is  discharged  without specifying the date, the court upon
  motion shall fix the date, except that where the date is certain and not
  in dispute, the date may be  fixed  by  the  clerk  of  the  court  upon
  affidavit.  The amount of interest shall be computed by the clerk of the
  court,  to  the  date the verdict was rendered or the report or decision
  was made, and included in the total sum awarded.