diff --git a/ledger/register.go b/ledger/register.go
index dd4e7b6..73facd3 100644
--- a/ledger/register.go
+++ b/ledger/register.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 	"log"
+	"maps"
 	"slices"
 	"time"
 )
@@ -41,23 +42,56 @@ func RegisterWithContributionPrediction(reg map[string]Balances, windowAsPercent
 		return result
 	}()
 
-	result := make(map[string]Balances)
+	result := maps.Clone(reg)
 	for name, datesBalance := range namesDatesBalance {
-		result[name] = func() Balances {
-			dates := func() []string {
-				result := make([]string, 0)
-				for k := range datesBalance {
-					result = append(result, k)
-				}
-				return result
-			}()
-			slices.Sort(dates)
+		dates := func() []int64 {
+			result := make([]int64, 0)
+			for k := range datesBalance {
+				v, _ := registerTime(k)
+				result = append(result, v.Unix())
+			}
+			slices.Sort(result)
+			return result
+		}()
+		weightedAverageContribution := func() map[Currency]float64 {
 			half := dates[len(dates)/2]
 			threeQuarter := dates[int(3.0*(len(dates)/4.0))]
 			sevenEighths := dates[int(7.0*(len(dates)/8.0))]
-         sum:= func(start, stop string) balance
-			panic(fmt.Sprintf("%s: %s .. %s .. %s (%v)", name, half, threeQuarter, sevenEighths, dates))
+			get := func(a, b int64) []Balance {
+				result := make([]Balance, 0)
+				for date, balance := range datesBalance {
+					v, _ := registerTime(date)
+					if v2 := v.Unix(); a <= v2 && v2 <= b {
+						result = append(result, balance)
+					}
+				}
+				return result
+			}
+			halfUp := get(half, threeQuarter)
+			threeQuarterUp := get(threeQuarter, sevenEighths)
+			sevenEighthsUp := get(sevenEighths, time.Now().Add(time.Hour*24*365).Unix())
+			weightedSum := make(map[Currency]float64, 0)
+			pushes := 0
+			pushWithWeight := func(b []Balance, weight int) {
+				for i, b2 := range b[1:] {
+					for c := range b2 {
+						v := b2[c] - b[i][c]
+						for i := 0; i < weight; i++ {
+							weightedSum[c] += v
+							pushes += 1
+						}
+					}
+				}
+			}
+			pushWithWeight(halfUp, 1)
+			pushWithWeight(threeQuarterUp, 2)
+			pushWithWeight(sevenEighthsUp, 4)
+			for k, v := range weightedSum {
+				weightedSum[k] = v / float64(pushes)
+			}
+			return weightedSum
 		}()
+		panic(fmt.Sprintf("%s: %v", name, weightedAverageContribution))
 	}
 	return result, nil
 }