[javascript] OVER_QUERY_LIMIT in Google Maps API v3: How do I pause/delay in Javascript to slow it down?

Here I have loaded 2200 markers. It takes around 1 min to add 2200 locations. https://jsfiddle.net/suchg/qm1pqunz/11/

//function to get random element from an array
    (function($) {
        $.rand = function(arg) {
            if ($.isArray(arg)) {
                return arg[$.rand(arg.length)];
            } else if (typeof arg === "number") {
                return Math.floor(Math.random() * arg);
            } else {
                return 4;  // chosen by fair dice roll
            }
        };
    })(jQuery);

//start code on document ready
$(document).ready(function () {
    var map;
    var elevator;
    var myOptions = {
        zoom: 0,
        center: new google.maps.LatLng(35.392738, -100.019531), 
        mapTypeId: google.maps.MapTypeId.ROADMAP
    };
    map = new google.maps.Map($('#map_canvas')[0], myOptions);

    //get place from inputfile.js
    var placesObject = place;
    errorArray = [];

  //will fire 20 ajax request at a time and other will keep in queue
    var queuCounter = 0, setLimit = 20; 

  //keep count of added markers and update at top
  totalAddedMarkers = 0;

  //make an array of geocode keys to avoid the overlimit error
    var geoCodKeys = [
                    'AIzaSyCF82XXUtT0vzMTcEPpTXvKQPr1keMNr_4',
                    'AIzaSyAYPw6oFHktAMhQqp34PptnkDEdmXwC3s0',
                    'AIzaSyAwd0OLvubYtKkEWwMe4Fe0DQpauX0pzlk',
                    'AIzaSyDF3F09RkYcibDuTFaINrWFBOG7ilCsVL0',
                    'AIzaSyC1dyD2kzPmZPmM4-oGYnIH_0x--0hVSY8'                   
                ];

  //funciton to add marker
    var addMarkers = function(address, queKey){
        var key = jQuery.rand(geoCodKeys);
        var url = 'https://maps.googleapis.com/maps/api/geocode/json?key='+key+'&address='+address+'&sensor=false';

        var qyName = '';
        if( queKey ) {
            qyName = queKey;
        } else {
            qyName = 'MyQueue'+queuCounter;
        }

        $.ajaxq (qyName, {
            url: url,
            dataType: 'json'
        }).done(function( data ) {
                    var address = getParameterByName('address', this.url);
                    var index = errorArray.indexOf(address);
                    try{
                        var p = data.results[0].geometry.location;
                        var latlng = new google.maps.LatLng(p.lat, p.lng);
                        new google.maps.Marker({
                            position: latlng,
                            map: map
                        });
                        totalAddedMarkers ++;

            //update adde marker count
                        $("#totalAddedMarker").text(totalAddedMarkers);
                        if (index > -1) {
                            errorArray.splice(index, 1);
                        }
                    }catch(e){
                        if(data.status = 'ZERO_RESULTS')
                            return false;

            //on error call add marker function for same address
            //and keep in Error ajax queue
                        addMarkers( address, 'Errror' );
                        if (index == -1) {
                            errorArray.push( address );
                        }
                    }
        });

    //mentain ajax queue set
        queuCounter++;
        if( queuCounter == setLimit ){
            queuCounter = 0;
        }
    }

  //function get url parameter from url string
    getParameterByName = function ( name,href )
    {
      name = name.replace(/[\[]/,"\\\[").replace(/[\]]/,"\\\]");
      var regexS = "[\\?&]"+name+"=([^&#]*)";
      var regex = new RegExp( regexS );
      var results = regex.exec( href );
      if( results == null )
        return "";
      else
        return decodeURIComponent(results[1].replace(/\+/g, " "));
    }

  //call add marker function for each address mention in inputfile.js
    for (var x = 0; x < placesObject.length; x++) {
        var address = placesObject[x]['City'] + ', ' + placesObject[x]['State'];
        addMarkers(address);
    }
});