[MINOR] Fix runtime plan cost estimator (createvar instruction)

Closes #1079.
diff --git a/src/main/java/org/apache/sysds/hops/cost/CostEstimator.java b/src/main/java/org/apache/sysds/hops/cost/CostEstimator.java
index fd670cc..bb8753c 100644
--- a/src/main/java/org/apache/sysds/hops/cost/CostEstimator.java
+++ b/src/main/java/org/apache/sysds/hops/cost/CostEstimator.java
@@ -215,7 +215,7 @@
 				long rlen = Long.parseLong(parts[6]);
 				long clen = Long.parseLong(parts[7]);
 				int blen = Integer.parseInt(parts[8]);
-				long nnz = Long.parseLong(parts[10]);
+				long nnz = Long.parseLong(parts[9]);
 				VarStats vs = new VarStats(rlen, clen, blen, nnz, false);
 				stats.put(varname, vs);
 			}