15.3.3.6 Leading Zeros
  To print leading zeros in a numeric field, you must start the
  format field with a zero enclosed in angle brackets (<0>).
  These characters also reserve one place for a digit.
  DECLARE STRING CONSTANT FM = "<0>####.##"
  PRINT USING FM, 1.23, 12.34, 123.45, 1234.56, 12345.67

  Output
  00001.23
  00012.34
  00123.45
  01234.56
  12345.67
  When you specify zero-fill, you cannot specify asterisk-fill or
  floating-dollar sign format for the same field.