jQuery pushing additional calculated data points to HighChart series

I am trying to push data points to a data series array for HighCharts. I have started with the standard pie template. I have then added additional $.get statements to calculate the number of lines in the files. The alert statement on each additional $.get returns the correct number of lines, but the data point is not pushed to the series. Can anyone help me, I am new to JQuery. Thanks.

                $.get('piechart.csv', function(data) {
                    // Split the lines
                    var buttons
                    var lines = data.split('\n');
                    var series = {
                        data: []
                    };
                    // Iterate over the lines and add categories or series
                    $.each(lines, function(lineNo,line) {
                        var items = line.split(',');
                            series.data.push({
                                name: items[0],
                                y:parseFloat(items[1])
                            });
                    });


                    $.get('button0.txt', function(data) {
                        // Split the lines
                        var lines = data.split('\n');
                        series.data.push({
                            name: 'Power off',
                            y: (lines.length-1)
                        });
                        alert (lines.length-1);
                    });
                    $.get('button1.txt', function(data) {
                        // Split the lines
                        var lines = data.split('\n');
                        series.data.push({
                            name: 'Power on',
                            y: (lines.length-1)
                        });
                        alert (lines.length-1);
                    });

                    options.series.push(series);
                    // Create the chart
                    var chart = new Highcharts.Chart(options);
                });