Were Almost All Greek New Testament Manuscript Textual Variants [Errors] Created Before 200 A.D.?

Colwell states: “the overwhelming majority of readings were created before the year 200.” Kilpatrick says, “almost all variants can be presumed to have been created by A.D. 200.” The Alands, say, “practically all the substantive variants in the text of the New Testament are from the second century …” Is this true?