The most common cause of this issue is the "Statistics Mode" on the Run>Configure tab has been set to "Quick".
Please ensure you set the mode to provide the desired level of statistics from the list below:
Full - provides Real-time, summary, and run-time statistics.
Brief - provides Real-time, summary without per-URL stats, and run-time statistics.
Summary - provides summary, and run-time statistics.
Quick - provides run-time statistics only.