diff --git a/ana/predictor.go b/ana/predictor.go
index f2d4812..93ecbca 100644
--- a/ana/predictor.go
+++ b/ana/predictor.go
@@ -46,7 +46,12 @@ func NewContributionPredictor(reg ledger.Register) Predictor {
 }
 
 func getMonthlyContributionRate(reg ledger.Register) map[string]ledger.Balance {
-	panic(nil)
+	contributions := getRecentContributions(reg)
+	result := make(map[string]ledger.Balance)
+	for name := range contributions {
+		panic(nil)
+	}
+	return result
 }
 
 func getRecentContributions(reg ledger.Register) map[string][]ledger.Balance {