How to resuse the same instance of a style - wpf

Question

I’m just testing some XAML stuff, and I am wondering why a style which comes from a resource dictionary is created multiple times when used inside a data template for listbox.
Let me give you an example
<UserControl x:Class="WpfApplication1.UserControl1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<ListBox ItemTemplate="{DynamicResource foo}" ItemsSource="{Binding Names}"/>
</UserControl>
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:wpfApplication1="clr-namespace:WpfApplication1">
<Window.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="Dictionary1.xaml" />
</ResourceDictionary.MergedDictionaries>
<DataTemplate x:Key="foo">
<TextBlock Style="{StaticResource TextBlockStyle}" Text="{Binding}" Loaded="TextBlock_Loaded"/>
</DataTemplate>
</ResourceDictionary>
</Window.Resources>
<wpfApplication1:UserControl1 />
</Window>
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Style x:Key="TextBlockStyle" TargetType="TextBlock">
<Setter Property="Background" Value="Red" />
<Setter Property="Foreground" Value="Pink" />
</Style>
</ResourceDictionary>
Now I’ve done a simple test in code behind to see whether the textblocks get the same style,
and it is surprising that each one of them gets a new instance of the same style, so if I had 50 records then I would have 50 instances of the same style.
Is that how people do it, or is there a pattern to reuse the same instance as many times as needed?
Thanks for looking :)