DHS RIOTS_2018 for Niger 1998 null values


I pulled DHS women survey data with the attached conflict data from ACLED (BATTLES, CIV_VIOLENCE, and RIOTS). For some reason, Niger 1998 sample has Null values for the variable RIOTS_2008 (that being the number of riots near each cluster for the year 2008) but is normal for all other RIOTS variable years and all other conflict variables as well.

I was wondering the reason behind this and if you have any suggestions on how to deal with the abnormality in my data as it stands? Were there just no riots in Niger in 2008?

Thank you for your help! I really appretiate it! =)