public function formatPercentEvolution($value)
    {
        $isPositiveEvolution = !empty($value) && ($value > 0 || $value[0] == '+');

        $formatted = self::formatPercent($value);

        if ($isPositiveEvolution) {
            // $this->symbols has already been initialized from formatPercent().
            $language = $this->translator->getCurrentLanguage();
            return $this->symbols[$language]['+'] . $formatted;
        }
        return $formatted;
    }