diff --git a/prometheus/counter.go b/prometheus/counter.go
index 756bb49..d463e36 100644
--- a/prometheus/counter.go
+++ b/prometheus/counter.go
@@ -15,7 +15,6 @@ package prometheus
 
 import (
 	"errors"
-	"fmt"
 	"math"
 	"sync/atomic"