Fan Xuan had been the Emperor for a few years.

Gao Zhan had been emperor for four years.

King Yu reigned for six years.

There were different versions of Xiao Jingyan's reign. Some said he had been in office for five years, some said he had been in office for two years, and some said he had been in office for 31 or 48 years. Overall, Xiao Jingyan's reign might have lasted between five to forty-eight years. Due to the lack of accurate information, it was impossible to determine how long Xiao Jingyan had been emperor.

Hong Xiuquan had been the emperor for 13 years.

There were different accounts of how long Xiao Jingyan had been emperor. Some said he had been in power for two years, some said he had been in power for five years, and some said he had been in power for 31 or 48 years. Overall, Xiao Jingyan's reign might have lasted between two to forty-eight years. Due to the lack of accurate information, it was impossible to determine how long Xiao Jingyan had been emperor.

The Emperor of Xia, Fan Xuan, was a wise ruler who thought for the country. He had put in a lot of effort to establish the Great Xia Kingdom, and had stabilized the court by arranging for Gu Jiusi to repair the Yellow River, making Liu Yuru fake her death, and investigating the Ministry of Revenue. Fan Xuan had also groomed young people like Gu Jiusi, Zhou Ye, Ye Shi 'an, and others, hoping that they could contribute to the future of Great Xia. However, Fan Xuan had left out his son, Fan Yu, in his plans. After Fan Yu became the Emperor, he was controlled by Luo Zishang, causing the Zhou family to suffer misfortune. When Fan Xuan finally passed away, he left behind the legacy of passing on the throne and deposing it, hoping to protect Great Xia from chaos for fifty years. However, Fan Yu did not listen to his father and became a puppet emperor under his control, bringing chaos and disaster to Xia. Fan Xuan's soft-heartedness and benevolence became his fatal weakness, leading to his tragic ending.

Ying Yiren had been the emperor for three years.

Yuwen Huaji had been emperor for half a year, but there was no specific information about how many years he had been emperor.

The reign of Gao Wei lasted for 12 years.

There was no clear number of times Fan Xian had been assassinated in " Celebrating Years." The search results mentioned that Fan Xian had been assassinated many times, including being poisoned at Fan manor, being assassinated at Hanging Temple, and being assassinated at Niulan Street. However, no exact number was provided to answer the exact number of times Fan Xian had been assassinated. Therefore, based on the information provided, I am unable to determine the exact number of times Fan Xian has been assassinated.