diff --git a/scripts/plot_parametrized.py b/scripts/plot_parametrized.py
index 48f354c15..d96177357 100755
--- a/scripts/plot_parametrized.py
+++ b/scripts/plot_parametrized.py
@@ -50,11 +50,11 @@ def extract_parameters(results):
             "benchmarks must all have the same parameter name, but found: %s"
             % sorted(names)
         )
-    return (next(iter(names)), values)
+    return (next(iter(names)), list(values))
 
 
 def unique_parameter(benchmark):
-    """Return the unique parameter `(name: str, value: float)`, or dies."""
+    """Return the unique parameter `(name: str, value: float)`, or die."""
     params_dict = benchmark.get("parameters", {})
     if not params_dict:
         die("benchmarks must have exactly one parameter, but found none")
@@ -63,7 +63,8 @@ def unique_parameter(benchmark):
             "benchmarks must have exactly one parameter, but found multiple: %s"
             % sorted(params_dict)
         )
-    return next(iter(params_dict.items()))
+    [(name, value)] = params_dict.items()
+    return (name, float(value))
 
 
 parameter_name = None
@@ -80,7 +81,6 @@ def unique_parameter(benchmark):
         )
     parameter_name = this_parameter_name
 
-    parameter_values = [float(pv) for pv in parameter_values]
     times_mean = [b["mean"] for b in results]
     times_stddev = [b["stddev"] for b in results]
 
diff --git a/src/hyperfine/export/csv.rs b/src/hyperfine/export/csv.rs
index 6260a2a46..28593a44a 100644
--- a/src/hyperfine/export/csv.rs
+++ b/src/hyperfine/export/csv.rs
@@ -16,16 +16,16 @@ impl Exporter for CsvExporter {
         let mut writer = WriterBuilder::new().from_writer(vec![]);
 
         {
-            let mut headers: Vec<String> = [
+            let mut headers: Vec<Cow<[u8]>> = [
                 // The list of times cannot be exported to the CSV file - omit it.
                 "command", "mean", "stddev", "median", "user", "system", "min", "max",
             ]
             .iter()
-            .map(|x| (*x).to_string())
+            .map(|x| Cow::Borrowed(x.as_bytes()))
             .collect();
             if let Some(res) = results.first() {
                 for param_name in res.parameters.keys() {
-                    headers.push(format!("parameter_{}", param_name));
+                    headers.push(Cow::Owned(format!("parameter_{}", param_name).into_bytes()));
                 }
             }
             writer.write_record(headers)?;