Catholics are the largest religious community in Pennsylvania, making up 29% of the state's adult population, followed by mainline Protestants at 25% and evangelical Protestants at 18%; white Catholics have been a pillar of Hillary Clinton's voter coalition in her big-state victories to date and are likely to be an important factor in the outcome of Tuesday's primary. Barack Obama has been working to expand his support beyond younger and more affluent Catholics, who have backed him in other states, to include older and blue-collar Catholics who have tended to support Clinton.

The Daily Number is a statistic, updated every weekday and typically drawn from Pew Research Center project findings, that highlights an important trend.

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