premise: SNOBOL ("StriNg Oriented and symBOlic Language") is a series of computer programming languages developed between 1962 and 1967 at AT&T Bell Laboratories by David J. Farber, Ralph E. Griswold and Ivan P. Polonsky, culminating in SNOBOL4. It was one of a number of text-string-oriented languages developed during the 1950s and 1960s; others included COMIT and TRAC.
hypothesis: It took 5 years to develop SNOBOL.
reason: The text states that SNOBOL was developed between 1962 and 1967, which is five years.