According to the publishers, it would take a single person 120 years to "key in" the 59 million words of the OED second edition, 60 years to proofread them, and 540 megabytes to store them electronically. As of 30 November 2005, the Oxford English Dictionary contained approximately 301,100 main entries. Supplementing the entry headwords, there are 157,000 bold-type combinations and derivatives; 169,000 italicized-bold phrases and combinations; 616,500 word-forms in total, including 137,000 pronunciations; 249,300 etymology; 577,000 cross-references; and 2,412,400 usage quotations. The dictionarys latest, complete print edition (second edition, 1989) was printed in 20 volumes, comprising 291,500 entries in 21,730 pages. The longest entry in the OED2 was for the verb set, which required 60,000 words to describe some 430 senses. As entries began to be revised for the OED3 in sequence starting from M, the longest entry became make in 2000, then put in 2007, then run in 2011.
Question: How many years in total would it take a single person to "key in" and proofread the 59 million words of the OED second edition?
Answer: 180