function outputTop10CountryNames($dbAdapter)
{
    $gateVisits = new VisitTableGateway($dbAdapter);
    $result = $gateVisits->findTop10CountryVisits();
    $countryNamesInfoArray = [];
    foreach ($result as $row) {
        $countryNamesInfo = new stdClass();
        $countryNamesInfo->countryISO = $row->ISO;
        $countryNamesInfo->countryName = $row->countryName;
        array_push($countryNamesInfoArray, $countryNamesInfo);
    }
    echo json_encode($countryNamesInfoArray);
}