Horizontally centering/evenly distributed <li> inside of <ul> inside a <div>

Have a Navbar <div>, inside is a <ul> and each <li> contains a <a> with a link (this is for a navigation bar)

I looked on Google and this site and I couldn't find exactly what I was looking for.

What I want is to be able to keep my current style (using <li> with <a>'s inside), and I want the <li> to be evenly distributed and centered (this part comes naturally if they are evenly distributed...) inside the <ul> (which is inside the navbar <div>).

Anyways, if that doesn't make sense let me know, currently they are just left aligned...here's what I have:

HTML:

<div class="navbar">
  <ul>
    <li><a href="Home">Home</a></li>
    <li><a href="Discounts">Discounts</a></li>
    <li><a href="Contact">Contact Us</a></li>
    <li><a href="About">About Us</a></li>
  </ul>
</div>

CSS:

.navbar {
    width: 100%;
    margin-left: auto ;
    margin-right: auto ;
    background-color: #ABCDEF;
}
.navbar ul {
    list-style-type: none; /*to remove bullets*/
    text-align: center;
    margin: 0px;
    padding: 0px;
    width: 90%;
    overflow: hidden;
}
.navbar li{
    float: left;
    padding: 2px;
    width: 150px;
    margin-left: auto ;
    margin-right: auto ;
}

I can also include my .navbar a{} if that is necessary. I am very new to CSS so go easy, also I did look all over SO and Google first and couldn't find anything quite like this (although maybe since I am new I don't realize it's the same).

If this is a faulty CSS method and/or there is a much easier, more commonly used way of doing this, go ahead and link/post that instead, but I would prefer this way as it makes most sense to me.