diff --git a/bin/coverage_report_single.py b/bin/coverage_report_single.py
index 877a1f0c..89948dad 100644
--- a/bin/coverage_report_single.py
+++ b/bin/coverage_report_single.py
@@ -479,7 +479,7 @@ def style_sub_threshold(self):
 
         dtypes = {
             'gene': str, 'tx': str, 'chrom': str, 'exon': int, 'exon_len': int,
-            'exon_start': int, 'exon_end': int, 'min': int, 'mean': int,
+            'exon_start': int, 'exon_end': int, 'min': int, 'mean': float,
             'max': int
         }