d3 shapes not appending from csv file

Question

I am trying to make a d3 scatter plot graph. I used d3.csv to load a csv file of data.

When I append the points of the data file none of the circle elements are appending to the canvas.

Code

<script>

var data;

//#############################################################################
//create domain and range of scatter plot for x and y
//#############################################################################
var svg = d3.select("body").append("svg").attr("width", 750).attr("height",500)

var xScale = d3.scale.linear().range([0,500]);

var yScale = d3.scale.linear().range([0,500]);

function render(data){
  xScale.domain(d3.extent(data, function(data){
    return data.year;
  }));

  yScale.domain(d3.extent(data, function(data){
    return data.avg_life;
  }));

  var points = svg.selectAll("circle")
                  .data(data)
                  .enter()
                  .append("circle")
                  .attr("r", 10)
                  .attr("cx", function(data){
                    xScale(data.year);
                  })
                  .attr("cy", function(data){
                    yScale(data.avg_life)
                  });
}

d3.csv("data.csv", function(d){
  data = d;
})
    </script>