2006: March, June, September, December
2007: March, June, September, December
2008: March, June, September, December
2009: February, June, October
2010: February, June, October
2011: February, June, October
2012: February, June, October
2013: February, June, October
2014: February, June, October
2015: February, June, October
2016: February, June, October
2017: February, June, October
2018: February, June, October
2019: March, June