5.5.1 Implicit Data Typing
  With implicit data typing, a data type for a variable is cre-
  ated and specified the first time you reference it. You specify
  the data type of the variable by a suffix on the variable name
  as follows:

  .
        A percent sign suffix ( % ) specifies the INTEGER data
        type.
  .
        A dollar sign suffix ( $ ) specifies the STRING data type.
  .
        Any other ending character specifies a variable of the
        default data type.

  The default data type is SINGLE; however, you can specify
  your own default at DCL command level, inside the BASIC
  environment, or with the OPTION statement in your pro-
  gram. For more information about establishing default data
  types, see Chapter 2 (VAX BASIC only) and Chapter 3 in this
  manual, and the OPTION statement in the DEC BASIC and
  VAX BASIC for OpenVMS Systems Reference Manual .

  The first time the variable is referenced, it creates a variable
  with that name and data type and allocates storage for that
  variable.

  In the following example, two INTEGER variables are cre-
  ated, A% and B% . Even though the values assigned to these
  variables are REAL, the values are converted to INTEGER to
  match the data type specified for the variables. The sum of
  these two values is therefore 30, not 30.6, as it would be if the
  variables were named A and B .
  A% = 10.1
  B% = 20.5
  PRINT A% + B%
    30

  With explicit data typing, you use a declarative statement to
  name and specify a data type for your program values.