Benyt baggrundsfarve på hver anden <tr>

Hej

Jeg har et lille PHP scrip, som henter nogle data fra en DB, men jeg vil gerne have at hver 2. tr bliver farvelag (for at gøre det mere overskueligt.

eks:
<table>
<tr>
  <td>
</tr>

<tr>
  <td bgcolor="000000">
</tr>

ovs...


Min kode ser sådan ud:

<table width="670" align="center" cellpadding="3" cellspacing="0" style="border: 1px solid #000000" class="text">
<tr>
  <td width="70" align="center" class="bottom-top"><b>Nummer</b></td>
  <td width="150" align="center" class="bottom-top"><b>Sted</b></td>
  <td width="60" align="center" class="bottom-top"><b>Dybde</b></td>
  <td width="90" align="center" class="bottom-top"><b>Tid</b></td>
  <td width="60" align="center" class="bottom-top"><b>Pris</b></td>
  <td width="80" align="center" class="bottom-top"><b>Dato</b></td>
  <td width="80" align="center" class="bottom-top"  style="border-left: 2px solid #000000;"><b>Rediger</b></td>
  <td width="80" align="center" class="bottom-top"><b>Slet</b></td>
</tr>


$query = mysql_query("SELECT * FROM logbog ORDER BY nummer");
while($row = mysql_fetch_assoc($query)) {

echo "

<tr>
  <td class=\"bottom\">" . $row["nummer"] . "</td>
  <td class=\"bottom\"><a href=\"visdata.php?nummer=" . $row["nummer"] . "\">" . $row["sted"] . "</a></td>
  <td align=\"right\" class=\"bottom\">" . $row["dybte"] . " m</td>
  <td align=\"right\" class=\"bottom\">" . $row["tid"] . " minutter</td>
  <td align=\"right\" class=\"bottom\">$pris kr. </td>
  <td align=\"right\" class=\"bottom\">" . $row["dato"] . "</td>
  <td align=\"center\" class=\"bottom\" style=\"border-left: 2px solid #000000;\" ><a href=\"rediger.php?nummer=" . $row["nummer"] . "\">Rediger</a></td>
  <td align=\"center\" class=\"bottom\"><a href=\"comfirm.php?nummer=" . $row["nummer"] . "\">Slet</a></td>
</tr>";


};