1987 - IIIP IIP IP P
1988 - IIIE IIE IE E Note that EI could also denote Q1 1974 or Q1 1984 etc
1989 - IIIN IIN IN N
1990 - IIIQ IIQ IQ Q
1991 - IIIU IIU IU U
1992 - IIIA IIA IA A
1993 - IIIL IIL IL L
1994 - IIII III II I
1995 - IIIT IIT IT T
1996 - IIIY IIY IY Y
1997 - IIIP IIP IP P
1998 - IIIE IIE IE E
1999 - IIIN IIN IN N
(change)
2000 - Q.III Q.II Q.I Q
2001 - U.III U.II U.I U
2002 - A.III A.II A.I A
2003 - L.III L.II L.I L
2004 - I.III I.II I.I I
2005 - T.III T.II T.I T
2006 - Y.III Y.II Y.I Y
2007 - P.III P.II P.I P
2008 - E.III E.II E.I E
2009 - N.III N.II N.I N