Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
Health in Kenya
Table title:
Child mortality
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 >  </th><th colspan=1 rowspan=1 > 1990 </th><th colspan=1 rowspan=1 > 2000 </th><th colspan=1 rowspan=1 > 2010 </th><th colspan=1 rowspan=1 > 2015 </th></tr>
<tr> <td colspan=1 rowspan=1 > Child mortality </td><td colspan=1 rowspan=1 > 98.1 </td><td colspan=1 rowspan=1 > 101 </td><td colspan=1 rowspan=1 > 62.2 </td><td colspan=1 rowspan=1 > 51.0 </td></tr>
<tr> <td colspan=1 rowspan=1 > Infant mortality </td><td class="highlighted"  colspan=1 rowspan=1 > 65.8 </td><td colspan=1 rowspan=1 > 66.5 </td><td colspan=1 rowspan=1 > 42.4 </td><td class="highlighted"  colspan=1 rowspan=1 > 35.5 </td></tr>
<tr> <td colspan=1 rowspan=1 > Neonatal mortality </td><td colspan=1 rowspan=1 > 27.4 </td><td colspan=1 rowspan=1 > 29.1 </td><td colspan=1 rowspan=1 > 25.9 </td><td class="highlighted"  colspan=1 rowspan=1 > 22.2 </td></tr>
</table>
Question:
How did the infant mortality rate change between 1990 and 2015?
Answer:
The infant mortality rate has reduced form 65.8 in 1990 to 35.5 in 2015.