According to the data released and the reports by Trac Immigration, it seems Obama's Immigration Priorities Executive Action, announced on November 20, 2014, has resulted in a decline in the use of ICE detainers.

Number of ICE Detainers Issued, October 2014 - October 2015

(Graph from Trac Immigraiton).

"Very recent government data on the use of detainers by Immigration and Customs Enforcement (ICE) indicates that the November 2014 order by the head of the Department of Homeland Security (DHS) abolishing ICE's Secure Communities program, and restricting detainer use to 'special circumstances' has so far only had a modest impact." - Trac Immigration

Take a look at the stats Trac has posted here.