What Letters And Numbers Has Kojima Productions Announced So Far?

Kojima Productions has been launching a seemingly endless stream of countdown clocks for an upcoming title. Ungh. Still! They seem to be offering clues. Let's recap.

To date, these letters have appeared on the Kojima "Next" site:

"S" (or number "5")
"R"
"P"
"E"
"C"
"@" (or a lowercase "e")
"O" (or number "0")

The following numbers have appeared:

"5" (or "S")
"3"
"6"
"0" (or letter "O")