SQL Server allows for only _____ levels of nesting in CASE expressions.

SQL Server allows for only 10 levels of nesting in CASE expressions.
ie:
DECLARE @A TINYINT
SELECT @A = 10
SELECT CASE WHEN @A>0 THEN
(CASE WHEN @A>1 THEN
(CASE WHEN @A>2 THEN
(CASE WHEN @A>3 THEN
(CASE WHEN @A>4 THEN
(CASE WHEN @A>5 THEN
(CASE WHEN @A>6 THEN
(CASE WHEN @A>7 THEN
(CASE WHEN @A>8 THEN
(CASE WHEN @A>9 THEN
(CASE WHEN @A=10 THEN
ELSE 'END' END)
ELSE 'END' END)
ELSE 'END' END)
ELSE 'END' END)
ELSE 'END' END)
ELSE 'END' END)
ELSE 'END' END)
ELSE 'END' END)
ELSE 'END' END)
ELSE 'END' END)
ELSE 'END' END

Err:
--------
Msg 125, Level 15, State 4, Line 13
Case expressions may only be nested to level 10.