diff --git a/sql/2020/11_Security/security_headers_prevalence.sql b/sql/2020/11_Security/security_headers_prevalence.sql
index f0830372f68..5cc9ba64e5b 100644
--- a/sql/2020/11_Security/security_headers_prevalence.sql
+++ b/sql/2020/11_Security/security_headers_prevalence.sql
@@ -9,6 +9,7 @@ CREATE TEMPORARY FUNCTION hasHeader(headers STRING, headername STRING)
 ''';
 
 SELECT
+  date,
   client,
   headername,
   COUNT(DISTINCT host) AS total_hosts,
@@ -16,19 +17,22 @@ SELECT
   COUNT(DISTINCT IF(hasHeader(headers, headername), host, NULL)) / COUNT(DISTINCT host) AS pct_with_header
 FROM (
   SELECT
+    date,
     client,
     NET.HOST(urlShort) AS host,
     JSON_EXTRACT(payload, '$.response.headers') AS headers
   FROM
     `httparchive.almanac.requests`
   WHERE
-    date = "2020-08-01" AND
+    (date = "2020-08-01" OR date = "2019-07-01") AND
     NET.HOST(urlShort) = NET.HOST(page)
 ),
 UNNEST(['Content-Security-Policy', 'Cross-Origin-Embedder-Policy', 'Cross-Origin-Opener-Policy', 'Cross-Origin-Resource-Policy', 'Expect-CT', 'Feature-Policy', 'Permissions-Policy', 'Referrer-Policy', 'Report-To', 'Strict-Transport-Security', 'X-Content-Type-Options', 'X-Frame-Options', 'X-XSS-Protection']) AS headername
 GROUP BY
+  date,
   client,
   headername
 ORDER BY
+  date,
   client,
   headername