demo.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Xml.Serialization;

static class P
{
    static void Main()
    {
        var xml = @"<Response><carList>
<numberOfRecords>237</numberOfRecords>
<year>1982</year>
<year>1983</year>
<year>1978</year>
<year>1955</year>
<year>1998</year>
</carList></Response>";

        var ser = new XmlSerializer(typeof(Response));
        var response = (Response)ser.Deserialize(new StringReader(xml));

        var carList = response.CarList;
        Console.WriteLine(carList.NumberOfRecords);
        if (carList.Year is not null)
        {
            foreach (var year in carList.Year)
            {
                Console.WriteLine(year);
            }
        }

    }
}
public class Response
{
    [XmlElement("carList")]
    public CarList? CarList { get; set; }
}

public class CarList
{
    [XmlElement("numberOfRecords")]
    public int? NumberOfRecords { get; set; }

    [XmlElement("year")]
    public List<string>? Year { get; set; }
}