In a prospective study of male British physicians, those who smoked only cigarettes and continued to smoke died, on average, about 10 years younger than lifetime nonsmokers.
Those who quit smoking at the ages of 60, 50, 40 and 30 years gained about 3, 6, 9 and 10 years of extra life, respectively [1].　

Worldwide, the annual number of deaths caused by smoking is about 5 million, and that caused by passive smoking is about 600,000.
In Japan, the annual number of deaths caused by smoking is estimated to be about 130,000, and by passive smoking, about 15,000 (lung cancer, ischemic disease, stroke) [2].

References

[1] R. Doll, R. Peto, J. Boreham, I. Sutherland, Mortality in relation to smoking: 50 years’ observations on male British doctors, BMJ, 328 (2004) 1519.
[2] National Cancer Center, Japan, Aggregation of survival rates for in-hospital cancer registries in hospitals and other centers for cancer care coordination, (2019).