DateTime :: year - Get number of years
The function returns the year from the date value, i.e. iYears from the iYears-iMonth-iDays date value.
Return value:  Year ( int32  )
Number of the year (AD).
Implementation overview
-  - internal feature (not documented)
 DateTime :: year (  )
-  - internal feature (not documented)
 DateTime :: year ( iYear )

