#include <bits/stdc++.h>
using namespace std;
void solve();
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout << fixed << setprecision(15);
  int t = 1;
  while (t--) solve();
  return 0;
}
int n, k;
vector<int> a;
vector<int> b;
long double get_val(int idx) {
  long double num = 100 * b[n - 1] - b[idx] * k;
  long double den = 100 * n - k * (idx + 1);
  return num / den;
}
void solve() {
  cin >> n >> k;
  a.assign(n, 0);
  b.assign(n, 0);
  for (int i = 0; i < (int)n; i++) cin >> a[i];
  sort((a).begin(), (a).end(), greater<int>());
  if (n == 1) {
    cout << (long double)a[0] << "\n";
    return;
  };
  b[0] = a[0];
  for (int i = 1; i < (int)n; i++) b[i] = a[i] + b[i - 1];
  for (int i = 0; i < (int)n - 1; i++) {
    long double val = get_val(i);
    if (a[i] >= val && val >= a[i + 1]) {
      cout << val << "\n";
      return;
    };
  }
}
