1917 defined the obligation of employers to pay for illnesses or accidents related to the workplace. It also defined social security as the institution to administer the right of workers, but only in 1943 was the Mexican Social Security Institute (IMSS) created. IMSS manages the Work Risks Insurance in a vertically integrated fashion, including registration of workers and firms, collection, classification of risks and events, and medical and rehabilitation services. A reform in 1997 defined that contributions are related to the experience of each employer. Public sector workers are covered by social security agencies with corporate and operative structures similar to those of IMSS. New Zealand In New Zealand, all companies that employ staff and in some cases others, must pay a levy to the Accident Compensation Corporation, a Crown entity, which administers New Zealand's universal no-fault accidental injury scheme. The scheme provides financial compensation and support to citizens, residents, and temporary visitors who have suffered personal injuries. United Kingdom Great Britain followed the German model. Joseph Chamberlain, leader of the Liberal Unionist party and coalition with the Conservatives, designed a plan that was enacted under the Salisbury government in 1897. The Workmen's Compensation Act 1897 was a key domestic achievement. It served its social purpose at no cost to the government, since compensation was paid for by insurance which employers were required to take out. The system operated from 1897 to 1946. It was expanded to include industrial diseases by the Workmen's Compensation Act 1906 and replaced by a state compensation scheme under the National Insurance (Industrial Injuries) Act 1946. Since 1976, this state scheme has been set out in the UK's Social Security Acts. Work related safety issues in the UK are supervised by the Health and Safety Executive (HSE), who provide the framework by which employers and employees are able to comply with statutory rules and regulations. Employer duties enforced by the HSE include protecting the health and safety of workers at workplace, risk assessment and training of workers. If an employer fails to fulfil these responsibilities, resulting in injury to an employee, then the employee has a legal right to make a workers' compensation claim against the employer and to sue their employer. With the exception of the following, all employers are obliged to purchase compulsory Employer's Liability Insurance in accordance with the Employer's Liability (Compulsory Insurance) Act 1969. The current minimum limit of indemnity required