DES MOINES — Iowa has collected more than $960 million in settlement funds to cover tobacco-related health costs since it participated in the landmark 1998 agreement with the nation’s major tobacco companies, state officials said Friday.Tobacco companies involved in the settlement with states — the largest settlement in U.S. history — transferred more than $71 million this week in their annual payment to Iowa, according to the state Attorney General’s Office.The sum included the regular yearly payment of more than $54 million as part of the master agreement and an additional “Strategic Contribution Fund” payment of more than $17.5 million.