The data is in, and there is no question that 2013 was the most active year for biotechnology initial public offerings since 2000. During the 12 months ended in December, 38 biotech companies debuted on Wall Street, all but two of which were listed on the Nasdaq exchange, according to FactSet, a Norwalk, Conn.-based provider of financial analytics. The performance of the biotech class of 2013 was rather impressive: As a group, the shares of the newly public companies rose 43% through the end of the year.