Привязать данные к progressbar`у в listBox`е

xaml:

<Window x:Class="ReadAndVerify.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:ReadAndVerify"
        xmlns:col="clr-namespace:System.Collections;assembly=mscorlib"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800" Background="#20201f" Foreground="White">
    <Window.Resources>
        <DataTemplate x:Key="ItemTemplate">
            <ProgressBar Value="{Binding}" Width="100" Height="20"/>
        </DataTemplate>
        <DataTemplate x:Key="SelectedTemplate">
            <TextBlock Text="{Binding Path=Title}" Foreground="White" />
        </DataTemplate>
        <Style TargetType="{x:Type ListBoxItem}" x:Key="ContainerStyle">
            <Setter Property="ContentTemplate" Value="{StaticResource ItemTemplate}" />
        </Style>
    </Window.Resources>
    <ListBox Name="lstCars" Margin="5" ItemContainerStyle="{StaticResource ContainerStyle}">
    </ListBox>
</Window>

c#:

private List<Project> _projects = Project.GetProjects();
public MainWindow()
{
    InitializeComponent();
    lstCars.ItemsSource = _projects;
}

Project.cs:

[Serializable]
public class Project
{
    [XmlIgnore]
    private static string pathToFile = @"..\..\Xml\Project.xml";
    public string Title { get; set; }
    [XmlElement("StartDate")]
    public DateTime StartDateForProject { get; set; }
    [XmlElement("FinishDate")]
    public DateTime FinishDateForProject { get; set; }
    public Project() { }
    public Project(string title,DateTime startDate, DateTime finishDate)
    {
        Title = title;
        StartDateForProject = startDate;
        FinishDateForProject = finishDate;
    }
    public override string ToString()
    {
        return "20";
    }
}

Если вместо {Binding} написать 20 - то все хорошо. А так привязываться не хочет? Почему - не пойму. Помогите плиз.