diff --git a/classes/metric/yearly_active_users_metric.php b/classes/metric/yearly_active_users_metric.php
index 4a53735..7bd3a5d 100644
--- a/classes/metric/yearly_active_users_metric.php
+++ b/classes/metric/yearly_active_users_metric.php
@@ -16,6 +16,9 @@
 
 namespace tool_cloudmetrics\metric;
 
+use progress_bar;
+use tool_cloudmetrics\lib;
+
 /**
  * Metric class for 12 months yearly active users.
  *
@@ -26,6 +29,19 @@
  */
 class yearly_active_users_metric extends builtin_user_base {
 
+
+    /** @var int The interval config for which data is displayed in seconds (eg: 5 minutes = 300). */
+    public $interval;
+
+    /** @var int The minimal timestamp representing earliest date retrieved in DB. */
+    public $mintimestamp;
+
+    /** @var int The maximal timestamp representing latest date retrieved in DB. */
+    public $maxtimestamp;
+
+    /** @var bool True if config used is same as one requested. */
+    public $sameconfig;
+
     /**
      * The metric's name.
      *
@@ -72,6 +88,15 @@ public function set_frequency(int $freq) {
         // Do nothing.
     }
 
+    /**
+     * Metric's ability to be backfilled.
+     *
+     * @return bool
+     */
+    public function is_backfillable(): bool {
+        return true;
+    }
+
     /**
      * Generates the metric items from the source data.
      *
@@ -91,4 +116,91 @@ public function generate_metric_item(int $starttime, int $finishtime): metric_it
         );
         return new metric_item($this->get_name(), $finishtime, $users, $this);
     }
+
+    /**
+     * Returns records for backfilled metric.
+     *
+     * @param int $backwardperiod Time from which sample is to be retrieved.
+     * @param int|null $finishtime If data is being completed argument is passed here.
+     * @param progress_bar|null $progress
+     *
+     * @return array
+     */
+    public function generate_metric_items(int $backwardperiod, ?int $finishtime = null, ?progress_bar $progress = null): array {
+        global $DB;
+        $metricitems = [];
+        $finishtime = ($finishtime === -1) ? null : $finishtime;
+        $finishtime = $finishtime ?? time();
+        $starttime = $finishtime - $backwardperiod;
+        // Back to last year from start time.
+        $lastyear = $starttime - YEARSECS;
+        // Get aggregation interval.
+        $frequency = $this->get_frequency();
+        $interval = lib::FREQ_TIMES[$frequency];
+        if ($finishtime < $starttime) {
+            return [];
+        }
+        $sql = 'SELECT floor(timecreated / :interval ) * :intervaldup AS timestamp,
+                        userid
+                  FROM {logstore_standard_log}
+                 WHERE timecreated >= :lastyear
+                   AND timecreated <= :finishtime
+              GROUP BY timestamp, userid
+              ORDER BY timestamp DESC';
+        $results = $DB->get_recordset_sql(
+            $sql,
+            ['interval' => $interval, 'intervaldup' => $interval, 'lastyear' => $lastyear, 'finishtime' => $finishtime]
+        );
+        $buffer = [];
+
+        foreach ($results as $record) {
+            $buffer[] = $record;
+        }
+        $results->close();
+
+        // Variables for updating progress.
+        $count = 0;
+        $total = ($finishtime - $starttime) / $interval;
+        // Build a metric for each day from starttime to finishtime.
+        while ($starttime <= $finishtime) {
+            $distinctusers = [];
+            $lastyear = $starttime - YEARSECS;
+            foreach ($buffer as $r) {
+                // Count active users in a 12 months period.
+                if ($r->timestamp >= $lastyear &&
+                    $r->timestamp <= $starttime &&
+                    !array_key_exists($r->userid, $distinctusers)) {
+                    $distinctusers[$r->userid] = true;
+                }
+            }
+            $metricitems[] = new metric_item($this->get_name(), $starttime, count($distinctusers), $this);
+            $starttime = $starttime + $interval;
+            $count++;
+            if ($progress) {
+                $progress->update(
+                    $count,
+                    $total,
+                    get_string('backfillgenerating', 'tool_cloudmetrics', $this->get_label())
+                );
+            }
+        }
+        $this->mintimestamp = !empty($metricitems) ? $metricitems[0]->time : null;
+        $this->maxtimestamp = !empty($metricitems) ? end($metricitems)->time : null;
+        $this->interval = $frequency;
+        return $metricitems;
+    }
+
+    /**
+     * Stores what data has been sent to collector.
+     *
+     */
+    public function set_data_sent_config(): void {
+        // Store what data has been sent min, max timestamp range and interval.
+        $currentconfig = [$this->mintimestamp, $this->maxtimestamp, $this->interval];
+        $rangeretrieved = $this->get_range_retrieved();
+        $this->sameconfig = ($rangeretrieved === $currentconfig);
+        if (!$this->sameconfig && isset($this->mintimestamp) && isset($this->maxtimestamp) && isset($this->interval)) {
+            $this->set_range_retrieved($currentconfig);
+        }
+    }
 }