Why does some of my columns in my HTML table display cells as undefined while other columns display correctly?

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">

<style>
    th{ 
        cursor: pointer;
        color:#fff;
            }
</style>


<table class="table table-striped">
    <tr  class="bg-info">
        <th  data-colname="date" data-order="desc">date &#9650</th>
        <th  data-colname="exposed" data-order="desc">exposed (mn) &#9650</th>
        <th  data-colname="displaced (k)" data-order="desc">displaced (k) &#9650</th>
        <th  data-colname="killed" data-order="desc">killed &#9650</th>
        <th  data-colname="duration(days)" data-order="desc">duration(days) &#9650</th>
        <th  data-colname="cause" data-order="desc">cause &#9650</th>
        <th  data-colname="Country Name" data-order="desc">Country Name &#9650</th>
        <th  data-colname="ISO code" data-order="desc">ISO code &#9650</th>
    </tr>
    <tbody id="myTable">
        
    </tbody>
</table>


<script>
var myArray =[{'date': '7/21/2007', 'exposed': 27712991, 'displaced (k)': 5000000, 'killed': 1071, 'duration(days)': 86, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '9/9/2010', 'exposed': 23137894, 'displaced (k)': 140000, 'killed': 0, 'duration(days)': 21, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '8/30/2008', 'exposed': 21631628, 'displaced (k)': 600000, 'killed': 0, 'duration(days)': 9, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '8/18/2008', 'exposed': 21529060, 'displaced (k)': 10000000, 'killed': 400, 'duration(days)': 37, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '7/12/2007', 'exposed': 21488636, 'displaced (k)': 11100000, 'killed': 96, 'duration(days)': 90, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '6/20/2004', 'exposed': 19855086, 'displaced (k)': 40000000, 'killed': 3000, 'duration(days)': 109, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '10/1/2010', 'exposed': 19362985, 'displaced (k)': 500000, 'killed': 15, 'duration(days)': 11, 'cause': 'Tropical StormSurge', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '7/25/2016', 'exposed': 18456496, 'displaced (k)': 25000, 'killed': 42, 'duration(days)': 32, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '9/1/2018', 'exposed': 17213562, 'displaced (k)': 1000, 'killed': 20, 'duration(days)': 6, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '6/11/2003', 'exposed': 16822143, 'displaced (k)': 9500000, 'killed': 600, 'duration(days)': 121, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '7/21/2002', 'exposed': 16541422, 'displaced (k)': 250000, 'killed': 380, 'duration(days)': 25, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '7/3/2007', 'exposed': 16486188, 'displaced (k)': 3000000, 'killed': 958, 'duration(days)': 81, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '9/16/2012', 'exposed': 15526445, 'displaced (k)': 200, 'killed': 45, 'duration(days)': 2, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '8/15/2011', 'exposed': 14830495, 'displaced (k)': 70000, 'killed': 158, 'duration(days)': 48, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '8/10/2017', 'exposed': 13271467, 'displaced (k)': 300000, 'killed': 117, 'duration(days)': 16, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '9/18/2010', 'exposed': 12414310, 'displaced (k)': 15000, 'killed': 88, 'duration(days)': 12, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '9/22/2008', 'exposed': 12372235, 'displaced (k)': 0, 'killed': 2400, 'duration(days)': 7, 'cause': 'Dam', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '10/7/2004', 'exposed': 11965543, 'displaced (k)': 100000, 'killed': 210, 'duration(days)': 11, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '8/20/2014', 'exposed': 11058729, 'displaced (k)': 500000, 'killed': 17, 'duration(days)': 19, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}, {'date': '9/22/2008', 'exposed': 8627859, 'displaced (k)': 13000, 'killed': 49, 'duration(days)': 7, 'cause': 'Heavy rain', 'Country Name': 'Nepal', 'ISO code': 'NPL'}]

buildTable(myArray)



 $('th').on('click', function(){
     var column = $(this).data('colname')
     var order = $(this).data('order')
     var text = $(this).html()
     text = text.substring(0, text.length - 1);
     
     
     
     if (order == 'desc'){
        myArray = myArray.sort((a, b) => a[column] > b[column] ? 1 : -1)
        $(this).data("order","asc");
        text += '&#9660'
     }else{
        myArray = myArray.sort((a, b) => a[column] < b[column] ? 1 : -1)
        $(this).data("order","desc");
        text += '&#9650'
     }

    $(this).html(text)
    buildTable(myArray)
    })


   
 
    
function buildTable(data){
    var table = document.getElementById('myTable')
    table.innerHTML = ''
    for (var i = 0; i < data.length; i++){
        var colname = `date-${i}`
        var colname = `exposed-${i}`
        var colname = `displaced (k)-${i}`
        var colname = `killed-${i}`
        var colname = `duration(days)-${i}`
        var colname = `cause-${i}`
        var colname = `Country Name-${i}`
        var colname = `ISO code-${i}`

        var row = `<tr>
                        <td>${data[i].date}</td>
                        <td>${data[i].exposed}</td>
                        <td>${data[i].displaced}</td>
                        <td>${data[i].killed}</td>
                        <td>${data[i].duration}</td>
                        <td>${data[i].cause}</td>
                        <td>${data[i].CountryName}</td>
                        <td>${data[i].ISOcode}</td>
                   </tr>`
        table.innerHTML += row
    }
}

</script>
<div id="time-range">
    <p>Time Range: <span class="slider-time"></span> - <span class="slider-time2"></span>
    </p> 
    
    <div class="sliders_step1">
        <div id="slider-range"></div>
    </div>
</div>