Large falls in church membership began at the start of this millennium. Statistics from 2015 show a drop-off of more than 37,000 baptised members, a fall of 2.1 per cent.
This takes the total Episcopal Church membership to a new low of fewer than 1.8 million.
Just four years earlier, in 2011, there were more than 1.9 million.
While nearly a quarter of churches grew by more than 10 per cent from 2011 to 2014, this was offset by the larger number - four in ten - that lost 10 per cent or more of their members over the same period.
The statistics have been analysed by Jeffrey Walton of Juicy Ecumenism who writes that the latest figures are consistent with past years.
"Dioceses in New England, the Rust Belt and predominantly rural areas post sharp declines, while dioceses in the South either retain their numbers or decline at a more gradual rate."
There were large membership declines in dioceses including New York, Newark, Maryland and Iowa.
However there was also growth in several dioceses including Central Florida, North Dakota, Hawaii, Nevada and Fort Worth.
More than seven in ten of Episcopal Church parishes attract fewer than 100 people to Sunday services.
Walton writes: "The trend lines do not bode well for the future, with 55 per cent of congregations experiencing decline of 10 per cent or greater in the past five years. In contrast, only 18 per cent of congregations grew their attendance by 10 per cent in the same time span. As a whole, the denomination has experienced a 26 per cent drop in attendance since 2005."
According to another recent report, one quarter of Episcopal congregations have a membership that is 50 per cent or more aged over 65, and in three-quarters of Episcopal congregations, more than half the members are aged over 50. The report says that growth is least likely to occur in churches with an older age profile.
Half of the membership is aged 50 or over. "The 'tipping point' in terms of likelihood of decline seems to be where over half of members are 50 years old or older," the report says.
The report acknowledges that most conservative, evangelical and sectarian religious bodies have been growing while mainline denominations have been in decline since the mid-1960s.
It also notes that the more Sunday services that are held, the more likely a church is to grow.
Earlier this year, the Church of England released figures which showed the number of people attending church services weekly has dipped below one million people for the first time, continuing an annual rate of decline of about one per cent.
The Archbishop of Canterbury Justin Welby is helping lead a "reform and renewal" movement in the Church of England in an attempt to reverse the decline.
The Episcopal Church's presiding bishop Michael Curry has focused on branding his church as the "Jesus movement".