I personally like to use the option labelsin pd.qcutto indicate clean and consistent labels.
np.random.seed([3,1415])
df = pd.DataFrame(dict(revenue=np.random.randint(1000000, 99999999, 100)))
df['decile'] = pd.qcut(df.revenue, 10, labels=range(10))
print(df.head())
@jeremycg, cat accessor
df.decile.cat.categories
Int64Index([0, 1, 2, 3, 4, 5, 6, 7, 8, 9], dtype='int64')
df.groupby('decile').describe().unstack()

df.query('decile >= 8')
revenue decile
4 98274570 9
6 99418302 9
19 89598752 8
20 88877661 8
22 90789485 9
29 83126518 8
31 90700517 9
33 96816407 9
40 89937348 8
54 83041116 8
65 83399066 8
66 97055576 9
79 87700403 8
81 88592657 8
82 91963755 9
83 82443566 8
84 84880509 8
88 98603752 9
95 92548497 9
98 98963891 9
z-score deciles
df = df.join(df.groupby('decile').revenue.agg(dict(Mean='mean', Std='std')), on='decile')
df['revenue_zscore_by_decile'] = df.revenue.sub(df.Mean).div(df.Std)
df.head()
revenue decile Std Mean revenue_zscore_by_decile
0 32951600 2 2.503325e+06 29649669 1.319018
1 70565451 6 9.639336e+05 71677761 -1.153928
2 6602402 0 5.395453e+06 11166286 -0.845876
3 82040251 7 2.976992e+06 78299299 1.256621
4 98274570 9 3.578865e+06 95513475 0.771500