Count years with Puppeteer - node.js

Question

I'm trying to count the total number of "year" from the following page:
See UPDATE below.
In my Nodejs script, I have:
await page.click(SELECT_YEARS_TO_VIEW);
await Promise.all([
page.waitForNavigation({ waitUntil: 'networkidle0' }),
page.waitForSelector('#ItemsTable > tbody > tr > td.DataItemSelections')
]);
const numberOfYears = (await page.$$('#ItemsTable > tbody > tr > td.DataItemSelections')).length;
console.log(`Years length: ${numberOfYears}.`);
It returns: Years length: 16.
Instead, in the Chrome console, if I run:
document.querySelectorAll('#ItemsTable > tbody > tr > td.DataItemSelections').length;
The (correct) output is: 39
I have read Puppeteer - counting elements in the DOM, but the suggestions inside it didn't resolve my problem.
UPDATE: the starting point is: https://unctadstat.unctad.org/wds/TableViewer/tableView.aspx?ReportId=96740
Then you have to click the icon "Select items to view" and then to "YEAR":
Here, the page where I need to count the number of the years:

Answer 1

The site is changing html based on scroll, you can open the dev tools and check the html tr tags change with the scroll, you can try and do the scroll to get the data but you can just intercept the response with all that data anyway.
Another way of counting the years,
await page.setRequestInterception(true);
page.on('response', async response => {
if (response.url().indexOf('https://unctadstat.unctad.org/wds/TableViewer/getItems.aspx') > -1) {
console.log(response.url());
console.log(await response.text()); // parse xml to json and count it
}
})
await Promise.all([
page.waitForNavigation({ waitUntil: 'networkidle0' }),
page.click(SELECT_YEARS_TO_VIEW)
]);