"The share of American adults in middle-income households also decreased, from 55% in 2000 to 51% in 2014," Pew Research Center reports. "At the same time, the share of adults in the upper-income tier increased from 17% to 20%."

Pew, which defines middle class as adults whose annual household income is two-thirds to double the national median ($55,775 as of 2016), details the national middle-income range for various household sizes.

Here's the breakdown of how much you have to earn each year to qualify as middle-income, depending on the size of your family:

Household of one: $24,042 to $72,126

Household of two: $34,000 to $102,001

The U.S. health care system has been subject to heated debate over the past decade, but one thing that has remained consistent is the level of performance, which has been ranked as the worst among industrialized nations for the fifth time, according to the 2014 Commonwealth Fund survey 2014. The U.K. ranked best with Switzerland following a close second.

The Commonwealth Fund report compares the U.S. with 10 other nations: France, Australia, Germany, Canada, Sweden, New Zealand, Norway, the Netherlands, Switzerland and the U.K. were all judged to be superior based on various factors. These include quality of care, access to doctors and equity throughout the country. Results of the study rely on data from the Organisation for Economic Co-operation and Development, the World Health Organization and interviews from physicians and patients.

Although the U.S. has the most expensive health care system in the world, the nation ranks lowest in terms of “efficiency, equity and outcomes,” according to the report. One of the most piercing revelations is that the high rate of expenditure for insurance is not commensurate to the satisfaction of patients or quality of service. High out-of-pocket costs and gaps in coverage “undermine efforts in the U.S. to improve care coordination,” the report summarized.

A striking take-home from the report was a need for equity throughout the nation. “Disparities in access to services signal the need to expand insurance to cover the uninsured and to ensure that all Americans have an accessible medical home,” it said. A lack of universal health care was noted as the key difference between the U.S. and the other industrial nations.

Pope Francis has said he is open to married men becoming priests to combat the Roman Catholic Church's shortage of clergy.

In an interview with German newspaper Die Zeit, Pope Francis said the lack of Catholic priests was an "enormous problem" for the Church, and indicated he would be open to a change in the rules governing eligibility for the priesthood.

"We need to consider if 'viri probati' could be a possibility," he said. "If so, we would need to determine what duties they could undertake, for example, in remote communities."

Viri probati is the Latin term for "tested men" or married men of outstanding faith and virtue. The option would allow men who are already married to be ordained as priests. But single men who are already priests would not be allowed to marry, according to the Pope.