Dimension rowcount = driver.findElement(By.xpath(".//*[@id='z_c']/tbody/tr[*]/th/a[1]/strong")).getSize();
System.out.println(rowcount);

List<WebElement> txt = driver.findElements(By.cssSelector("table.d_g.d_g1>tbody>tr"));
System.out.println(txt.size());

<table id="z_c" class="d_g d_gl" summary="List of news items">
<tbody>
<tr class="fgskip" style="visibility:hidden;">
<tr class="d_gactr">
<tr class="d_gh">
<tr>
<td class="d_gd_sel" style="white-space:nowrap;padding-left:0px;border-bottom:none;">
<th class="d_gdb d_ich" scope="row">
<a class="vui-link" href="/d2l/lms/news/newedit.d2l?ou=6606&newsId=998&Global=0" title="Edit US Elections">
<strong>**US Elections**</strong>
</a>
<a id="z_o" class="dcm dcm_handle" role="button" aria-haspopup="true" tabindex="0" title="Actions for US Elections">
<span id="z_p" style="display:none;">
</th>
<td class="d_gn d_gc d_gdb" style="padding-right:0.9em;padding-left:0.9em;">
<td class="d_gn d_gc d_gdb" style="padding-right:0.9em;padding-left:0.9em;">
<td class="d_gn d_gc d_gdb" style="padding-right:0.9em;padding-left:0.9em;">
</tr>
<tr class="d_detailsRow">
<td class="d_gd" style="border-right:none"> </td>
<td class="d_gd" colspan="4">
<div id="z_q" class="drt" style="margin-top:0.9em;display: block;">
<p>**Elections will start on the 8 November**</p>
</div>
<div class="dco" style="margin-top:0.9em;margin-bottom:0.9em;">
</td>
</tr>
<tr>
<tr class="d_detailsRow">
<tr>
<tr class="d_detailsRow">
<tr>
<tr class="d_detailsRow">
<tr>
<tr class="d_detailsRow">
<tr>
<tr class="d_detailsRow">
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<tr class="d_detailsRow">
<tr>
<tr class="d_detailsRow">
<tr>
<tr class="d_detailsRow">
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<tr class="d_detailsRow">
<tr>
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<tr>

<tr class="d_detailsRow">
<tr>
<tr class="d_detailsRow">
<tr>
<tr class="d_detailsRow">
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<tr class="d_detailsRow">
<tr>
<tr class="d_detailsRow">
<tr>
<tr class="d_detailsRow d_lastRow">
<tr class="d_gactr">
</tbody>
</table>