A crisis of sorts is developing in the appointment of Catholic bishops worldwide as a backlog of 187 sees (not including China) remain vacant.

According to figures on Catholic-Hierarchy.org, eight U.S. dioceses are without a bishop, plus two U.S. eparchies (dioceses of Eastern rite churches).

These include the diocese of Bridgeport, Connecticut which hasn’t had a bishop since March 2012 when Mons. William Lori was appointed Archbishop of Baltimore.

Others include Harrisburg, Pennsylvania; Fort Worth, Texas; Rochester, NY; and Marquette, Michigan, vacated by Mons. Alexander Sample in January on his appointment as Archbishop of Portland, Oregon.

Half of Scotland’s ordinaries – four out of eight – have yet to be appointed, including the archdiocese of St. Andrews and Edinburgh which suddenly fell vacant in February after the resignation of Cardinal Keith Patrick O’Brien.

The Philippines, meanwhile, has nine sees without a bishop. In January this year, retired Filipino Archbishop Oscar Cruz noted there were then 10 vacant sees in the country and thought it might be the highest number in recent history. He wondered if the Vatican might have been having a hard time in appointing new bishops for the country.

“Maybe they are looking for a certain qualification, a way of doing things or a way of thinking…there is no fast rule on this really,” he said, adding he was not worried as he was confident the Vatican would soon appoint new bishops.

England also has two important dioceses that need a bishop: the archdiocese of Liverpool, vacant since February, and Leeds which has been without an ordinary since June 2012.

Italy is one of those countries faring the worst: 12 vacant sees, two vacant territorial abbeys, and one eparchy.

Meanwhile, some dioceses, such as Wilcannia-Forbes in Australia and Mansa in Zambia, haven’t had a bishop since 2009.

Sees that fell vacant during Benedict's pontificate, and which remain so, number the most – 131 out of 187. Since Pope Francis was elected, 36 dioceses fell vacant and continue to be without a bishop.

Vatican spokesman Father Federico Lombardi said he was unaware of the reasons, and did not know what the average period is for dioceses to remain without a bishop. But he added he “wouldn’t be surprised” if, during the time of transition from one pontificate to another, and with “everything that has significance for the normal operation of ecclesiastical institutions, a certain delay in pending procedures has resulted.”

Since his election, the Holy Father has had many pressing duties competing for his attention, not least reforming the Roman Curia and the Vatican Bank. But delays in the appointment of bishops is becoming a concern, and one no doubt he will wish to tackle sooner rather than later.