Concerning the Episcopal Church:

The research page of the Episcopal Church website provides detailed research and statistics: http://www.episcopalchurch.org/research.htm
 
Please note:

Dioceses and congregations remain part of the Episcopal Church even when local leaders and/or a number of parishioners opt to leave the denomination as a matter of personal choice.

Dioceses are created by the General Convention and cannot be dissolved without action of the General Convention in accordance with the provisions of the churchwide constitution and canons. Congregations, likewise, are created by a local diocese and continue within that structure unless otherwise decided by the local bishop in consultation with other elected diocesan leaders.

According to an October 2008 update from director of research Kirk Hadaway, out of some 7100 total Episcopal Church congregations, located inside and outside the U.S., since 2003:

• There were 33 congregations in which the majority of the members have voted to leave the Episcopal Church, meaning that either at least 50 % of the members of the congregation left or the church closed and the diocese re-started the congregation.
• There are 40 congregations in which the majority of the members have left the Episcopal Church, meaning the diocese allowed them to leave, or the diocese closed the church after the congregation left
• There are 10 congregations in which the majority of the members voted to leave but the congregations remain a part of the Episcopal Church

(These figures do not include the Diocese of San Joaquin)