yield_2019 = AFLT[AFLT["YEAR"] == 2019]["LOGYIELD"]
yield_2019 *= 100



k = int(1 + 3.322 * np.log(len(yield_2019)) / np.log(10))
R = max(yield_2019) - min(yield_2019)
h = round(R / k,2)
interval = [round(i,2) for i in np.arange(min(yield_2019) + delta,max(yield_2019) - delta,h)]
interval.append(round(interval[-1] + h,2))
interval

sorted_yields = sorted(yield_2019)


def cnt_range(li, min, max):
    ctr = 0
    for x in li:
        if min < x <= max:
            ctr += 1
    return ctr
rows, cols = [], []
for i in range(len(interval) - 1):
    a, b = interval[i], interval[i+1]
    cols.append(f'({a}:{b}]')
    rows.append(cnt_range(sorted_yields, a, b))

df_yields = pd.DataFrame(data=[rows], columns=cols, index = ['count'])
df_yields