This paper analyzes the hourly load curve of the total electricity demand using the most detailed information available for the Colombian electricity market. Our findings are the following: first, regulated and non-regulated markets have very different load curves; for the regulated market, the load curve has pronounced peaks and valleys while for the non-regulated market the load curve is approximately flat. All economic sectors have a flat load curve, except those whose activity is related to an hourly schedule as agriculture, livestock, fishing or commerce. Second, load factor has changed from 0.70 to 0.82; this variation is explained for the corresponding growth of the load factor in the regulated market; the non-regulated market has an approximately constant load factor. And third, cluster analysis indicates that demand can be grouped in two classes of typical days: the first cluster correspond to Sundays and holidays and the second cluster to the other days.