diff --git a/Cargo.toml b/Cargo.toml
index 2254dfd..48b8958 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,3 +6,4 @@ license = "MIT/Apache-2.0"
 description = "Fast functions for printing integer primitives to an io::Write"
 repository = "https://github.com/dtolnay/itoa"
 documentation = "https://github.com/dtolnay/itoa"
+include = ["Cargo.toml", "src/**/*.rs"]
diff --git a/README.md b/README.md
index aae2a73..3e6b74e 100644
--- a/README.md
+++ b/README.md
@@ -11,6 +11,10 @@ implementation comes straight from
 but avoids the performance penalty of going through
 [`fmt::Formatter`](https://doc.rust-lang.org/std/fmt/struct.Formatter.html).
 
+## Performance
+
+![performance](https://raw.githubusercontent.com/dtolnay/itoa/master/performance.png)
+
 ## Functions
 
 ```rust
diff --git a/performance.png b/performance.png
new file mode 100644
index 0000000..1e23b71
Binary files /dev/null and b/performance.png differ