diff --git a/src/bin/solve/simple.rs b/src/bin/solve/simple.rs
index a71b947..aa7f996 100644
--- a/src/bin/solve/simple.rs
+++ b/src/bin/solve/simple.rs
@@ -7,7 +7,7 @@ use libpt::log::*;
 
 use wordle_analyzer::game::response::GuessResponse;
 
-use wordle_analyzer::solve::{stupid, BuiltinSolverNames, NaiveSolver, Solver, StupidSolver};
+use wordle_analyzer::solve::{BuiltinSolverNames, Solver};
 use wordle_analyzer::wlist::builtin::BuiltinWList;
 use wordle_analyzer::wlist::word::Word;
 use wordle_analyzer::{self, game};
diff --git a/src/wlist/mod.rs b/src/wlist/mod.rs
index 6f545e6..2cd029c 100644
--- a/src/wlist/mod.rs
+++ b/src/wlist/mod.rs
@@ -47,7 +47,7 @@ pub trait WordList: Clone + std::fmt::Debug + Default {
         WordMap::from(hm)
     }
     fn get_word(&self, word: &Word) -> Option<WordData>;
-    fn letter_frequency(&self) -> WordMap {
+    fn letter_frequency(&self) -> HashMap<char, Frequency> {
         // PERF: this function has complexity O(n²)!
         let mut cmap: HashMap<char, usize> = HashMap::new();
         // count the chars in each word
@@ -58,8 +58,8 @@ pub trait WordList: Clone + std::fmt::Debug + Default {
                 }
             }
         }
-        // make all chars to strings
-        let cmap: HashMap<Word, usize> = cmap.into_iter().map(|p| (p.0.to_string(), p.1)).collect();
-        WordMap::from_absolute(cmap)
+        // convert to relative frequency
+        let n: f64 = cmap.keys().len() as f64;
+        cmap.into_iter().map(|p| (p.0, p.1 as f64 / n)).collect()
     }
 }
diff --git a/src/wlist/word.rs b/src/wlist/word.rs
index 785f4ea..2385a2e 100644
--- a/src/wlist/word.rs
+++ b/src/wlist/word.rs
@@ -103,3 +103,9 @@ impl From<HashMap<Word, Frequency>> for WordMap {
         Self { inner: value }
     }
 }
+
+impl From<WordMap > for HashMap<Word, Frequency>{
+    fn from(value: WordMap) -> Self {
+        value.inner
+    }
+}