Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE Roles ( role_code CHAR(15), role_description VARCHAR(255) )
TABLE: CREATE TABLE Document_Drafts ( document_id INTEGER, draft_number INTEGER, draft_details VARCHAR(255) )
TABLE: CREATE TABLE Documents ( document_id INTEGER, document_status_code CHAR(15), document_type_code CHAR(15), shipping_agent_code CHAR(15), receipt_date DATETIME, receipt_number VARCHAR(255), other_details VARCHAR(255) )
TABLE: CREATE TABLE Addresses ( address_id INTEGER, address_details VARCHAR(255) )
TABLE: CREATE TABLE Ref_Document_Types ( document_type_code CHAR(15), document_type_description VARCHAR(255) )
TABLE: CREATE TABLE Ref_Document_Status ( document_status_code CHAR(15), document_status_description VARCHAR(255) )
TABLE: CREATE TABLE Documents_Mailed ( document_id INTEGER, mailed_to_address_id INTEGER, mailing_date DATETIME )
TABLE: CREATE TABLE Ref_Shipping_Agents ( shipping_agent_code CHAR(15), shipping_agent_name VARCHAR(255), shipping_agent_description VARCHAR(255) )
TABLE: CREATE TABLE Employees ( employee_id INTEGER, role_code CHAR(15), employee_name VARCHAR(255), other_details VARCHAR(255) )
TABLE: CREATE TABLE Draft_Copies ( document_id INTEGER, draft_number INTEGER, copy_number INTEGER )
TABLE: CREATE TABLE Circulation_History ( document_id INTEGER, draft_number INTEGER, copy_number INTEGER, employee_id INTEGER )

### Question ###
How many employees does each role have? Plot a bar chart listing role id and number of employees, display by the role_code in descending please.

### Accurate SQL ###

SELECT T1.role_code, COUNT(*) FROM Roles AS T1 JOIN Employees AS T2 ON T1.role_code = T2.role_code GROUP BY T2.role_code ORDER BY T1.role_code DESC