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:
Zhengzhou Open
Table title:
Singles
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Year </th><th colspan=1 rowspan=1 > Champion </th><th colspan=1 rowspan=1 > Runner-up </th><th colspan=1 rowspan=1 > Score </th></tr>
<tr> <td colspan=5 rowspan=1 > ↑ WTA Premier event ↑ </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 2018 </td><td colspan=1 rowspan=1 > China Zheng Saisai </td><td colspan=1 rowspan=1 > China Wang Yafan </td><td colspan=1 rowspan=1 > 5–7, 6–2, 6–1 </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 2017 </td><td colspan=1 rowspan=1 > China Wang Qiang </td><td colspan=1 rowspan=1 > China Peng Shuai </td><td colspan=1 rowspan=1 > 3–6, 7–6(7–3), 1–1 ret. </td></tr>
<tr> <td colspan=5 rowspan=1 > ↑ WTA 125K event ↑ </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 2016 </td><td colspan=1 rowspan=1 > Russia Anastasia Pivovarova </td><td colspan=1 rowspan=1 > China Lu Jingjing </td><td colspan=1 rowspan=1 > 6–4, 6–4 </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 2015 </td><td colspan=1 rowspan=1 > China Wang Yafan </td><td colspan=1 rowspan=1 > China Duan Yingying </td><td colspan=1 rowspan=1 > 6–4, 6–4 </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 2014 </td><td colspan=1 rowspan=1 > China Zhang Kailin </td><td colspan=1 rowspan=1 > China Xu Yifan </td><td colspan=1 rowspan=1 > 7–5, 6–4 </td></tr>
<tr> <td colspan=5 rowspan=1 > ↑ ITF event ↑ </td></tr>
</table>
Question:
What year did the Zhengzhou Open was first held as an ITF tournamenrvand when did it transition to a WTA type tournament?
Answer:
The Zhengzhou Open has been held since 2014, as an ITF tournament and then as WTA 125K tournament in 2017 and 2018.