Goldman Sachs Group Inc. doesn’t publish statistics on how many partners leave each year, and the company stopped issuing press releases about partner promotions in 2006.  But based on internal memos, company filings and news reports, the 5th-biggest U.S. bank by assets is estimated to have lost at least 37 partners in 2011 in the firm's worst year for profit and share performance since 2008. Nine partners were added from outside the firm in 2011 - including 6 when Goldman Sachs took full control of its Australian joint venture.  In addition, Goldman Sachs, since its IPO in 1998, has promoted its top performers to partner level every 2 years - the next class will be promoted in 2012.  In 2006, Goldman's 2nd-largest class, 115 were promoted  to partner, while in 2010, 110 people were promoted. At the close of last year, Goldman had 475 partners - up from 221 in 1998.  As the firm's biggest shareholders, partner held a combined stake of 13.8% as of 11/20/11 - up from 10.25% as of 1/27/11. The current partner departures probably are tied to the firm's intention to cut annual expenses by $1.2 billion - which could translate into some 1,000 job cuts.  With partner departures, including retirements, the firm effectively achieves larger cuts than if they terminated a lower-ranked employee. Among those leaving: 4 who became partners before the 1999 IPO, including Kevin Kennedy, 63, who became a partner in 1984.  That leaves only 2 partners from the 1980's  - Chairman and CEO Lloyd Blankfein, 57, and John Curtin Jr., 61 - both named in 1988.  Curtin, a U.S. citizen, is Toronto-based chairman and CEO of the firm’s Canadian operations. “The work is terribly hard and so people don’t stay around usually in this line of work for all that long,” said Charles Ellis, author of the 2008 book “The Partnership: The Making of Goldman Sachs.” “The intensity gets to you.” Some partners who retire, nevertheless maintain ties to the company through business relationships, alumni events or so-called advisory-director or senior-director roles.  Joseph Gleberman, for one, after working at Goldman for more than 29 years - most recently as chief risk officer in merchant banking - and who became a partner in 1990, plans to serve as an advisory director on the investment committee after retiring this year-end. For a Full List of Departing Partners, go to;  [Bloomberg 12/14/11].