change sg typo

Author: chinandrew

safegraph/README.md

@@ -1,9 +1,9 @@
-# Safegraph Mobility Data
+#   Safegraph Mobility Data
 
-We import raw mobility data from Safegraph, calculate some 
-statistics upon it, and aggregate the data from the Zip Code level to County,
-HRR, MSA and State levels. For detailed information see the files `DETAILS.md` 
-contained in this directory.
+We import raw mobility data from Safegraph, calculate some statistics upon it,
+and aggregate the data from the Census Block Group to County and State levels.
+For detailed information see the files `DETAILS.md` contained
+in this directory.
 
 ## Running the Indicator