diff --git a/gitinspector/output/blameoutput.py b/gitinspector/output/blameoutput.py
index 683f2ec..677b432 100644
--- a/gitinspector/output/blameoutput.py
+++ b/gitinspector/output/blameoutput.py
@@ -107,7 +107,7 @@ class BlameOutput(Outputable):
 			stability_xml = ("\t\t\t\t\"stability\": " + "{0:.1f}".format(Blame.get_stability(i[0], i[1].rows,
 			                 self.changes)) + ",\n")
 			age_xml = ("\t\t\t\t\"age\": " + "{0:.1f}".format(float(i[1].skew) / i[1].rows) + ",\n")
-			percentage_in_comments_xml = ("\t\t\t\t\"percentage-in-comments\": " + "{0:.2f}".format(100.0 * i[1].comments / i[1].rows) +
+			percentage_in_comments_xml = ("\t\t\t\t\"percentage_in_comments\": " + "{0:.2f}".format(100.0 * i[1].comments / i[1].rows) +
 			                              "\n")
 			blame_xml += ("{\n" + name_xml + gravatar_xml + rows_xml + stability_xml + age_xml +
 			             percentage_in_comments_xml + "\t\t\t},")
diff --git a/gitinspector/output/changesoutput.py b/gitinspector/output/changesoutput.py
index b42417d..7a6b773 100644
--- a/gitinspector/output/changesoutput.py
+++ b/gitinspector/output/changesoutput.py
@@ -115,7 +115,7 @@ class ChangesOutput(Outputable):
 				commits_xml = "\t\t\t\t\"commits\": " + str(authorinfo.commits) + ",\n"
 				insertions_xml = "\t\t\t\t\"insertions\": " + str(authorinfo.insertions) + ",\n"
 				deletions_xml = "\t\t\t\t\"deletions\": " + str(authorinfo.deletions) + ",\n"
-				percentage_xml = "\t\t\t\t\"percentage-of-changes\": " + "{0:.2f}".format(percentage) + "\n"
+				percentage_xml = "\t\t\t\t\"percentage_of_changes\": " + "{0:.2f}".format(percentage) + "\n"
 
 				changes_xml += ("{\n" + name_xml + gravatar_xml + commits_xml + insertions_xml +
 				                deletions_xml + percentage_xml + "\t\t\t}")
diff --git a/gitinspector/output/metricsoutput.py b/gitinspector/output/metricsoutput.py
index ebf31ee..43f9286 100644
--- a/gitinspector/output/metricsoutput.py
+++ b/gitinspector/output/metricsoutput.py
@@ -103,7 +103,7 @@ class MetricsOutput(Outputable):
 			if self.metrics.eloc:
 				for i in sorted(set([(j, i) for (i, j) in self.metrics.eloc.items()]), reverse=True):
 					eloc_xml += "{\n\t\t\t\t\"type\": \"estimated-lines-of-code\",\n"
-					eloc_xml += "\t\t\t\t\"file-name\": \"" + i[1] + "\",\n"
+					eloc_xml += "\t\t\t\t\"file_name\": \"" + i[1] + "\",\n"
 					eloc_xml += "\t\t\t\t\"value\": " + str(i[0]) + "\n"
 					eloc_xml += "\t\t\t},"
 				else:
@@ -113,7 +113,7 @@ class MetricsOutput(Outputable):
 			if self.metrics.cyclomatic_complexity:
 				for i in sorted(set([(j, i) for (i, j) in self.metrics.cyclomatic_complexity.items()]), reverse=True):
 					eloc_xml += "{\n\t\t\t\t\"type\": \"cyclomatic-complexity\",\n"
-					eloc_xml += "\t\t\t\t\"file-name\": \"" + i[1] + "\",\n"
+					eloc_xml += "\t\t\t\t\"file_name\": \"" + i[1] + "\",\n"
 					eloc_xml += "\t\t\t\t\"value\": " + str(i[0]) + "\n"
 					eloc_xml += "\t\t\t},"
 				else:
@@ -123,7 +123,7 @@ class MetricsOutput(Outputable):
 			if self.metrics.cyclomatic_complexity_density:
 				for i in sorted(set([(j, i) for (i, j) in self.metrics.cyclomatic_complexity_density.items()]), reverse=True):
 					eloc_xml += "{\n\t\t\t\t\"type\": \"cyclomatic-complexity-density\",\n"
-					eloc_xml += "\t\t\t\t\"file-name\": \"" + i[1] + "\",\n"
+					eloc_xml += "\t\t\t\t\"file_name\": \"" + i[1] + "\",\n"
 					eloc_xml += "\t\t\t\t\"value\": {0:.3f} \"\n".format(i[0])
 					eloc_xml += "\t\t\t},"
 				else:
diff --git a/gitinspector/output/timelineoutput.py b/gitinspector/output/timelineoutput.py
index 2c04038..ab35d44 100644
--- a/gitinspector/output/timelineoutput.py
+++ b/gitinspector/output/timelineoutput.py
@@ -136,7 +136,7 @@ class TimelineOutput(Outputable):
 		if self.changes.get_commits():
 			message_xml = "\t\t\t\"message\": \"" + _(TIMELINE_INFO_TEXT) + "\",\n"
 			timeline_xml = ""
-			periods_xml = "\t\t\t\"period-length\": \"{0}\",\n".format("week" if self.useweeks else "month")
+			periods_xml = "\t\t\t\"period_length\": \"{0}\",\n".format("week" if self.useweeks else "month")
 			periods_xml += "\t\t\t\"periods\": [\n\t\t\t"
 
 			timeline_data = timeline.TimelineData(self.changes, self.useweeks)