NEW YORK — Seymour Siwoff, the statistics maven who turned the Elias Sports Bureau into the place to go for exact information on teams and athletes for more than a half-century, died Friday. He was 99.

In keeping with Siwoff’s penchant for detail, he died at his home in Manhattan at 12:57 p.m. EST, according to grandson Joe Gilston, who took control of the company in March when 100 percent of Elias’ stock was bought by The Joseph Gilston Trust. Siwoff still went to the office regularly until a few months ago, Gilston said.

Elias was started in 1913 by brothers Al Munro Elias and Walter Bruce Elias and became official statistician of baseball’s National League in 1919. Siwoff, born on Nov. 1, 1920, started as an accountant in 1938 and purchased the company in 1952 from the brothers’ widows.

The company eventually consolidated its baseball work around 1980 when it replaced the Sports Information Center as the American League’s official statistician and fro, 1981 until the 2006 it compiled statistics that were used to determine baseball’s free-agent compensation levels.