ls sfos1994pdf | wc -l   ==> 25 (files start in June)
 ls sfos1995pdf | wc -l   ==> 45
 ls sfos1996pdf | wc -l   ==> 44
 ls sfos1997pdf | wc -l   ==> 35 (missing July and August)
 ls sfos1998pdf | wc -l   ==> 46
 ls sfos1999pdf | wc -l   ==> 44
 ls sfos2000pdf | wc -l   ==> 52
 ls sfos2001pdf | wc -l   ==> 52
 ls sfos2002pdf | wc -l   ==> 52
 ls sfos2003pdf | wc -l   ==> 48
 ls sfos2004pdf | wc -l   ==> 47
 ls sfos2005pdf | wc -l   ==> 50
 ls sfos2006pdf | wc -l   ==> 46
 ls sfos2007pdf | wc -l   ==> 51
 ls sfos2008pdf | wc -l   ==> 44
 ls sfos2009pdf | wc -l   ==> 47
 ls sfos2010pdf | wc -l   ==> 46
 ls sfos2011pdf | wc -l   ==> 48
 ls sfos2012pdf | wc -l   ==> 46
 ls sfos2013pdf | wc -l   ==> 46
 ls sfos2014pdf | wc -l   ==> 49
 ls sfos2015pdf | wc -l   ==> 48
 ls sfos2016pdf | wc -l   ==> 49
 ls sfos2017pdf | wc -l   ==> 48
 ls sfos2018pdf | wc -l   ==> 47
 ls sfos2019pdf | wc -l   ==> 47
 ls sfos2020pdf | wc -l   ==> 52
 ls sfos2021pdf | wc -l   ==> 51
 ls sfos2022pdf | wc -l   ==> 47
 ls sfos2023pdf | wc -l   ==> 51
 ls sfos2024pdf | wc -l   ==> 53
 ls sfos2025pdf | wc -l   ==> 50