Boles' ID Card issued 2005. His Asylum bio says he's been working for 8 years at the Asylum. Taking this information, Arkham Asylum takes place in 2013. If Frank is hired right as the Asylum reopens, Arkham Origins would take place in 2003 or 2004, City in 2014, Knight in 2015 and SS:KTJL in 2020.