The occurrence rate of halo CMEs from 1996 to the end of 2013. The occurrence rate of halo CMEs (number per Carrington rotation) from 1996 to the end of 2013 detected by SOHO/LASCO. From 1 December 2008 to 31 December 2013, there were 186 halo CMEs. Over the corresponding phase in cycle 23 (10 May 1996 to 9 June 2001), there were only 162 halos. If the halos occurred with the same average rate during the 4-month period when SOHO was operational, the number is expected to be approximately 173. Thus, the number of full halos in cycle 24 is comparable to that of cycle 23 or slightly greater (data from Gopalswamy et al. 2015).