diff --git a/pkgs/build-support/setup-hooks/make-coverage-analysis-report.sh b/pkgs/build-support/setup-hooks/make-coverage-analysis-report.sh
index 4b8abb61ace..9108b4c5035 100644
--- a/pkgs/build-support/setup-hooks/make-coverage-analysis-report.sh
+++ b/pkgs/build-support/setup-hooks/make-coverage-analysis-report.sh
@@ -10,9 +10,16 @@ coverageReportPhase() {
     mkdir -p $out/coverage
     genhtml app.info $lcovExtraTraceFiles -o $out/coverage > log
 
-    # Grab the overall coverage percentage for use in release overviews.
+    # Grab the overall coverage percentage so that Hydra can plot it over time.
     mkdir -p $out/nix-support
-    grep "Overall coverage rate" log | sed 's/^.*(\(.*\)%).*$/\1/' > $out/nix-support/coverage-rate
+    lineCoverage="$(sed 's/.*lines\.*: \([0-9\.]\+\)%.*/\1/; t ; d' log)"
+    functionCoverage="$(sed 's/.*functions\.*: \([0-9\.]\+\)%.*/\1/; t ; d' log)"
+    if [ -z "$lineCoverage" -o -z "$functionCoverage" ]; then
+        echo "failed to get coverage statistics"
+        exit 1
+    fi
+    echo "lineCoverage $lineCoverage %" >> $out/nix-support/hydra-metrics
+    echo "functionCoverage $functionCoverage %" >> $out/nix-support/hydra-metrics
 
     echo "report coverage $out/coverage" >> $out/nix-support/hydra-build-products
 }