A new report looks at the budget crises facing 13 American cities, including Boston. Tough Decisions and Limited Options: How Philadelphia and Other Cities are Balancing Budgets in a Time of Recession was released yesterday by the Pew Charitable Trusts.

Boston is actually among the better-off cities. The authors estimate a current budget gap of $140 million, equal to 6 percent of the city’s general fund. Compare that to Detroit, which has a $300 million shortfall equal to 20 percent of its general fund.

As the chart below shows (click it for a sharper image), Boston relies heavily on property tax revenue, which is relatively stable. By comparison, Phoenix is dependent on sales tax revenue and state aid, both of which are in serious decline. That city has an estimated deficit of $201 million, or 17 percent of its general fund. Philadelphia’s dependence on a wage tax has also put it in a bigger hole than Boston’s.