Complex sentence: The membership was reduced to 54 when Edward McMillan-Scott was expelled from the group in July 2009, and again increased to 55 when Anna Rosbach joined the group in March 2011.
Split into simpler sentences: The membership was reduced to 54 when Edward McMillan-Scott was expelled from the group in July 2009. It increased to 55 again when Anna Rosbach joined the group in March 2011.