66 1.66 1.66 ...</span>
<span class="r-out co"><span class="r-pr">#&gt;</span>  $ milemp : int  2687 2696 2693 2694 2690 2687 2696 2693 2690 2680 ...</span>
<span class="r-out co"><span class="r-pr">#&gt;</span>  $ gprc   : num  NA NA NA NA NA NA NA NA NA NA ...</span>
<span class="r-out co"><span class="r-pr">#&gt;</span>  $ gcem   : num  NA 0.113 0.19 0.251 0.218 ...</span>
<span class="r-out co"><span class="r-pr">#&gt;</span>  $ gprcpet: num  NA 0 0 0 0 0 0 0 0 0 ...</span>
<span class="r-out co"><span 