Micro Focus is a main player in Cobol landscape. If the survey was answered by their clients, those numbers are to be expected. Besides, for any language is to be expected a growth in the number of lines in production; software projects are always raising their line count, so only a big decrease in the number of systems running Cobol would yield to a decreasing number of lines.
Remove COBOL is a very slow process. It can take decades for a big organization. And new lines of code must be written for the transition. And until the new systems are ready, you have to keep adding new features to the old ones.
Next headline: MySpace is growing, according to a global survey conducted by MySpace.