Some of the country’s best-known multi­national corporations closely guard a number they don’t want anyone to know: the breakdown between their jobs here and abroad.

So secretive are these companies that they hand the figure over to government statisticians on the condition that officials will release only an aggregate number. The latest data show that multinationals cut 2.9 million jobs in the United States and added 2.4 million overseas between 2000 and 2009.